| 1. |
- Quinn, Patrick D., et al.
(author)
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Childhood attention-deficit/hyperactivity disorder symptoms and the development of adolescent alcohol problems : A prospective, population-based study of Swedish twins
- 2016
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In: American Journal of Medical Genetics Part B. - Hoboken, USA : John Wiley & Sons. - 1552-4841 .- 1552-485X. ; 171:7, s. 958-970
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Journal article (peer-reviewed)abstract
- Children with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of problematic alcohol and other substance use in adolescence. This study used data from an ongoing, prospective, population-based twin study of Swedish children and adolescents to evaluate the extent to which the association between ADHD symptoms and alcohol problems reflects a unique source of genetic or environmental risk related to ADHD versus a broader predisposition to youth externalizing behavior. We used all available data from same-sex monozygotic (MZ) and dizygotic (DZ) twins on ADHD symptoms in childhood (age 9/12; N = 15,549) and alcohol problems in late adolescence (age 18; N = 2,564). Consistent with prior longitudinal studies, the phenotypic association between hyperactive/impulsive ADHD symptoms and alcohol problems was small in magnitude, whereas the association for inattentive symptoms was even weaker. Additive genetic influences explained 99.8% of the association between hyperactive/impulsive symptoms and alcohol problems. Furthermore, we found that the genetic risk specifically associated with hyperactive/impulsive symptoms was attenuated when estimated in the context of externalizing behavior liability during childhood, of which ADHD symptoms were specific expressions. In sensitivity analyses exploring hyperactivity in mid-adolescence, we found a similar pattern of genetic associations. These results are consistent with previous findings of genetically driven overlap in the etiology of ADHD and problematic alcohol use. At least some of this co-occurrence may result from a general predisposition to externalizing behaviors in youth. © 2015 Wiley Periodicals, Inc.
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| 2. |
- Rydell, Mina, et al.
(author)
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Genetic and environmental contributions to the association between ADHD and affective problems in early childhood : A Swedish population-based twin study
- 2017
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In: American Journal of Medical Genetics Part B. - Stockholm : John Wiley & Sons. - 1552-4841 .- 1552-485X. ; 174:5, s. 538-546
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Journal article (peer-reviewed)abstract
- Few twin studies have explored the relative contribution of genetic and environmental factors to the association between attention deficit hyperactivity disorder (ADHD) and affective problems, and no study has focused on preschool children. We used the classical twin design to explore the genetic and environmental overlap between ADHD symptoms and affective problems in preschool children, based on 879 five-year-old twin pairs born in Sweden 2004-2005. Questionnaire-based parent-ratings were used to measure ADHD symptoms and affective problems. A bivariate twin design was used to decompose variance in ADHD and affective problems into genetic and environmental components, and to test the degree to which these components overlapped across the two traits. Our results showed that there was a significant correlation of 0.34 (95% Confidence Interval [CI] 0.29-0.38) between ADHD and affective problems. This correlation was mostly explained by additive genetic factors (64%, 95%CI 37-93%), and to a lesser extent by shared environmental factors (35%, 95%CI 10-59%). Nonshared environmental factors did not contribute to the correlation between ADHD and affective problems (0%, 95%CI -9 to 10%). These findings show that there is a significant association between ADHD and affective problems in preschool children that is mostly explained by genetic influences. This adds important knowledge about the etiology of both ADHD and affective problems by indicating that these phenotypes are linked from as early as preschool years. This also needs to be taken into consideration when diagnosing young children and clinicians should consider assessing both affective problems and ADHD if one is present.
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| 3. |
- Agartz, I, et al.
(author)
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BDNF gene variants and brain morphology in schizophrenia
- 2006
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In: American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics. - : Wiley. - 1552-4841. ; 141B:5, s. 513-523
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Journal article (peer-reviewed)
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| 4. |
- Akingbuwa, W. A., et al.
(author)
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Multivariate analyses of molecular genetic associations between childhood psychopathology and adult mood disorders and related traits
- 2022
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In: American Journal of Medical Genetics Part B-Neuropsychiatric Genetics. - : Wiley. - 1552-4841 .- 1552-485X. ; 192:1-2, s. 3-12
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Journal article (peer-reviewed)abstract
- Ubiquitous associations have been detected between different types of childhood psychopathology and polygenic risk scores based on adult psychiatric disorders and related adult outcomes, indicating that genetic factors partly explain the association between childhood psychopathology and adult outcomes. However, these analyses in general do not take into account the correlations between the adult trait and disorder polygenic risk scores. This study aimed to further clarify the influence of genetic factors on associations between childhood psychopathology and adult outcomes by accounting for these correlations. Using a multivariate multivariable regression, we analyzed associations of childhood attention-deficit/hyperactivity disorder (ADHD), internalizing, and social problems, with polygenic scores (PGS) of adult disorders and traits including major depression, bipolar disorder, subjective well-being, neuroticism, insomnia, educational attainment, and body mass index (BMI), derived for 20,539 children aged 8.5-10.5 years. After correcting for correlations between the adult phenotypes, major depression PGS were associated with all three childhood traits, that is, ADHD, internalizing, and social problems. In addition, BMI PGS were associated with ADHD symptoms and social problems, while neuroticism PGS were only associated with internalizing problems and educational attainment PGS were only associated with ADHD symptoms. PGS of bipolar disorder, subjective well-being, and insomnia were not associated with any childhood traits. Our findings suggest that associations between childhood psychopathology and adult traits like insomnia and subjective well-being may be primarily driven by genetic factors that influence adult major depression. Additionally, specific childhood phenotypes are genetically associated with educational attainment, BMI and neuroticism.
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| 5. |
- Alaerts, Maaike, et al.
(author)
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Detailed analysis of the serotonin transporter gene (SLC6A4) shows no association with bipolar disorder in the Northern Swedish population
- 2009
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In: American Journal of Medical Genetics Part B: Neuropsychiatric Genetics. - : John Wiley & Sons, Inc. - 1552-4841 .- 1552-485X. ; 150B:4, s. 585-592
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Journal article (peer-reviewed)abstract
- Through active reuptake of serotonin into presynaptic neurons, the serotonin transporter (5-HTT) plays an important role in regulating serotonin concentrations in the brain, and it is the site of binding for tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs). Therefore it has been hypothesized that this transporter is involved in the etiology of bipolar (BP) disorder. Inconsistent association study results for the SLC6A4 gene encoding 5-HTT reported in literature emphasize the need for more systematic and detailed analyses of this candidate gene. We performed an extensive analysis of SLC6A4 on DNA of 254 BPI patients and 364 control individuals from a Northern Swedish isolated population. This analysis consisted of a HapMap LD-based association study including three widely investigated polymorphisms (5-HTTVNTR, 5-HTTLPR, and rs3813034), a copy-number variation (CNV) analysis and a mutation analysis of the complete coding sequence and the 3'-UTR of SLC6A4. No single marker showed statistically significant association with BPI, nor did any of the haplotypes. In the mutation analysis 13 novel variants were detected, including 2 amino acid substitutions M389V and 1587L, but these are probably not implicated in risk for BP. No deletions or duplications were detected in the CNV analysis. We conclude that variation in the SLC6A4 gene or its regulatory regions does not contribute to the susceptibility for BP disorder in the Northern Swedish population.
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| 6. |
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| 7. |
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| 8. |
- Bena, Frederique, et al.
(author)
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Molecular and clinical characterization of 25 individuals with exonic deletions of NRXN1 and comprehensive review of the literature
- 2013
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In: American Journal of Medical Genetics Part B. - : Wiley. - 1552-4841 .- 1552-485X. ; 162B:4, s. 388-403
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Journal article (peer-reviewed)abstract
- This study aimed to elucidate the observed variable phenotypic expressivity associated with NRXN1 (Neurexin 1) haploinsufficiency by analyses of the largest cohort of patients with NRXN1 exonic deletions described to date and by comprehensively reviewing all comparable copy number variants in all disease cohorts that have been published in the peer reviewed literature (30 separate papers in all). Assessment of the clinical details in 25 previously undescribed individuals with NRXN1 exonic deletions demonstrated recurrent phenotypic features consisting of moderate to severe intellectual disability (91%), severe language delay (81%), autism spectrum disorder (65%), seizures (43%), and hypotonia (38%). These showed considerable overlap with previously reported NRXN1-deletion associated phenotypes in terms of both spectrum and frequency. However, we did not find evidence for an association between deletions involving the -isoform of neurexin-1 and increased head size, as was recently published in four cases with a deletion involving the C-terminus of NRXN1. We identified additional rare copy number variants in 20% of cases. This study supports a pathogenic role for heterozygous exonic deletions of NRXN1 in neurodevelopmental disorders. The additional rare copy number variants identified may act as possible phenotypic modifiers as suggested in a recent digenic model of neurodevelopmental disorders.
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| 9. |
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| 10. |
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| 11. |
- Blom, Elin Susanne, et al.
(author)
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Does APOE explain the linkage of Alzheimer’s disease to chromosome 19q13?
- 2008
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In: American Journal of Medical Genetics Part B: Neuropsychiatric Genetics American Journal of Medical Genetics Part B: Neuropsychiatric Genetics. - : Wiley. - 1552-485X. ; 147B:6, s. 778-83
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Journal article (peer-reviewed)abstract
- We have studied the impact of the apolipoprotein E gene (APOE) on the chromosome 19 linkage peak from an analysis of sib-pairs affected by Alzheimer's disease. We genotyped 417 affected sib-pairs (ASPs) collected in Sweden and Norway (SWE), the UK and the USA for 10 microsatellite markers on chromosome 19. The highest Zlr (3.28, chromosome-wide P-value 0.036) from the multi-point linkage analysis was located approximately 1 Mb from APOE, at marker D19S178. The linkage to chromosome 19 was well explained by APOE in the whole sample as well as in the UK and USA subsamples, as identity by descent (IBD) increased with the number of epsilon 4 alleles in ASPs. There was a suggestion from the SWE subsample that linkage was higher than would be expected from APOE alone, although the test for this did not reach formal statistical significance. There was also a significant age at onset (aao) effect on linkage to chromosome 19q13 in the whole sample, which manifested itself as increased IBD sharing in relative pairs with lower mean aao. This effect was partially, although not completely, explained by APOE. The aao effect varied considerably between the different subsamples, with most of the effect coming from the UK sample. The other samples showed smaller effects in the same direction, but these were not significant.
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| 12. |
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| 13. |
- Bremer, Anna, et al.
(author)
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Copy number variation characteristics in subpopulations of patients with autism spectrum disorders.
- 2011
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In: American Journal of Medical Genetics, Part B, Neuropsychiatric Genetics. - : Wiley. - 1552-4841. ; 156B156:2, s. 115-124
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Journal article (peer-reviewed)abstract
- Autism spectrum disorders (ASDs) are a heterogeneous group of disorders with a complex genetic etiology. We used high-resolution whole genome array-based comparative genomic hybridization (array-CGH) to screen 223 ASD patients for gene dose alterations associated with susceptibility for autism. Clinically significant copy number variations (CNVs) were identified in 18 individuals (8%), of which 9 cases (4%) had de novo aberrations. In addition, 20 individuals (9%) were shown to have CNVs of unclear clinical relevance. Among these, 13 cases carried rare but inherited CNVs that may increase the risk for developing ASDs, while parental samples were unavailable in the remaining seven cases. Classification of all patients into different phenotypic and inheritance pattern groups indicated the presence of different CNV patterns in different patient groups. Clinically relevant CNVs were more common in syndromic cases compared to non-syndromic cases. Rare inherited CNVs were present in a higher proportion of ASD cases having first- or second-degree relatives with an ASD-related neuropsychiatric phenotype in comparison with cases without reported heredity (P=0.0096). We conclude that rare CNVs, encompassing potential candidate regions for ASDs, increase the susceptibility for the development of ASDs and related neuropsychiatric disorders giving us further insight into the complex genetics underlying ASDs
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| 14. |
- Bremer, Anna, et al.
(author)
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Screening for Copy Number Alterations in Loci Associated With Autism Spectrum Disorders by Two-Color Multiplex Ligation-Dependent Probe Amplification
- 2010
-
In: American journal of medical genetics. Part B, Neuropsychiatric genetics. - : Wiley. - 1552-4841 .- 1552-485X. ; 153B:1, s. 280-285
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Journal article (peer-reviewed)abstract
- The autism spectrum disorder (ASD) is a heterogenous condition characterized by impaired socialization and communication in association with stereotypic behaviors. ASD is highly heritable and heterogeneous with a complex genetic etiology. Recurrent submicroscopic deletions or duplications have been identified in a subgroup of individuals with ASD using array technology. Adequate genetic testing for these genomic imbalances have not yet been widely implemented in the diagnostic setting due to lack of feasible and cost-effective methods as well as difficulties to interpret the clinical significance of these small copy number variants (CNVs). We developed a multiplex ligation-dependent probe amplification (MLPA) assay to investigate its usefulness for detection of copy number alterations (CNAs) in autistic patients. This test proved to be easy to perform, fast, cost-effective, and suitable for reliable detection of multiple loci in a single reaction. We screened 148 autistic patients for 15 different loci covering 26 genes and found a 15q11-13 interstitial duplication that had escaped detection by conventional karyotyping in 1.3% of the patients. Synthetic probe MLPA allows for a flexible analysis of a continuously increasing number of CNAs associated with autism. Our result show that MLPA assay is an easy and cost-effective method for the identification of selected CNAs in diagnostic laboratories. (C) 2009 Wiley-Liss, Inc.
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| 15. |
- Brikell, Isabell, et al.
(author)
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Heritability of attention-deficit hyperactivity disorder in adults
- 2015
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In: American Journal of Medical Genetics Part B. - Hoboken, USA : Wiley-Blackwell. - 1552-4841 .- 1552-485X. ; 168:6, s. 406-413
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Research review (peer-reviewed)abstract
- Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder. Symptoms often persist into adulthood, with a prevalence of 2.5-5% in adult populations. Twin studies in childhood consistently report high heritabilities of 70-80%, while studies in adult samples show only moderate heritability of 30-40% when estimated from self-ratings. This review summarizes the available research on the heritability of ADHD in adults. Three key findings are outlined: (i) self-ratings lead to relatively low heritability estimates of ADHD, independent of age and whether ratings refer to current or retrospective symptoms; (ii) studies relying on different informants to rate each twin within a pair (i.e., self-ratings and different parents/teachers rating each twin in a pair) consistently yield lower heritability estimates than studies relying on ratings from a single informant; (iii) studies using cross-informant data via either combined parent and self-ratings or clinical diagnoses information suggest that the heritability of ADHD in adults could be as high as 70-80%. Together, the reviewed studies suggest that the previously reported low heritability of ADHD in adults is unlikely to reflect a true developmental change. Instead, the drop in heritability is better explained by rater effects related to a switch from using one rater for both twins in a pair (parent/teacher) in childhood, to relying on self-ratings (where each twin rates themselves) of ADHD symptoms in adulthood. When rater effects are addressed using cross-informant approaches, the heritability of ADHD in adults appears to be comparable to the heritability of ADHD in childhood.
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| 16. |
- Bulik, CM, et al.
(author)
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Selection of eating-disorder phenotypes for linkage analysis
- 2005
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In: American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics. - : Wiley. - 1552-4841. ; 139B:1, s. 81-87
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Journal article (peer-reviewed)
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| 17. |
- Buxbaum, Joseph D, et al.
(author)
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Mutation screening of the PTEN gene in patients with autism spectrum disorders and macrocephaly.
- 2007
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In: American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics. - : Wiley. - 1552-4841 .- 1552-485X. ; 144B:4, s. 484-491
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Journal article (peer-reviewed)abstract
- Mutations in the PTEN gene are associated with a broad spectrum of disorders, including Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome, Proteus syndrome, and Lhermitte-Duclos disease. In addition, PTEN mutations have been described in a few patients with autism spectrum disorders (ASDs) and macrocephaly. In this study, we screened the PTEN gene for mutations and deletions in 88 patients with ASDs and macrocephaly (defined as >or=2 SD above the mean). Mutation analysis was performed by direct sequencing of all exons and flanking regions, as well as the promoter region. Dosage analysis of PTEN was carried out using multiplex ligation-dependent probe amplification (MLPA). No partial or whole gene deletions were observed. We identified a de novo missense mutation (D326N) in a highly conserved amino acid in a 5-year-old boy with autism, mental retardation, language delay, extreme macrocephaly (+9.6 SD) and polydactyly of both feet. Polydactyly has previously been described in two patients with Lhermitte-Duclos disease and CS and is thus likely to be a rare sign of PTEN mutations. Our findings suggest that PTEN mutations are a relatively infrequent cause of ASDs with macrocephaly. Screening of PTEN mutations is warranted in patients with autism and pronounced macrocephaly, even in the absence of other features of PTEN-related tumor syndromes.
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| 18. |
- Castensson, Anja, et al.
(author)
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Serotonin Receptor 2C (HTR2C) and Schizophrenia : Examination of Possible Medication and Genetic Influences on Expression Levels
- 2005
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In: American Journal of Medical Genetics. - : Wiley. - 0148-7299 .- 1096-8628. ; 134B, s. 84-89
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Journal article (peer-reviewed)abstract
- The serotonin receptor 2C (HTR2C) gene is of interest in schizophrenia due to its involvement in regulation of dopamine activity in the prefrontal cortex. We have previously reported a decreased expression of HTR2C mRNA levels in the prefrontal cortex of schizophrenia patients. The variability in mRNA expression levels is evaluated here more closely in relation to promoter haplotypes and neuroleptic treatment received by the patients. The decrease in HTR2C mRNA was present in neuroleptic treated individuals and in patients untreated at death, indicating that the lower expression is not a short-term medication effect. Three promoter polymorphisms were used to construct haplotypes. No SNP displayed genotypic or haplotypic association with the disease. Gene expression of HTR2C was not affected by haplotype and the expression decrease in schizophrenia patients was similar in all haplotype combinations (diplotypes). We conclude that the decrease in HTR2C expression in schizophrenia may be related to the disease mechanism rather than to drug treatment. The disease related changes in HTR2C expression are not related to the promoter variants typed in our sample, but could be due to other regulatory variants or trans-acting factors.
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| 19. |
- Chaste, Pauline, et al.
(author)
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Mutation screening of the ARX gene in patients with autism.
- 2007
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In: American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics. - : Wiley. - 1552-4841 .- 1552-485X. ; 144B:2, s. 228-230
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Journal article (peer-reviewed)abstract
- Mutations in the Aristaless related homeobox (ARX) gene are associated with a broad spectrum of disorders, including nonsyndromic X-linked mental retardation, sometimes associated with epilepsy, as well as syndromic forms with brain abnormalities and abnormal genitalia. Furthermore, ARX mutations have been described in a few patients with autism or autistic features. In this study, we screened the ARX gene in 226 male patients with autism spectrum disorders and mental retardation; 42 of the patients had epilepsy. The mutation analysis was performed by direct sequencing of all exons and flanking regions. No ARX mutations were identified in any of the patients tested. These findings indicate that mutations in the ARX gene are very rare in autism.
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| 20. |
- Chen, Long Long, et al.
(author)
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Genomics of severe and treatment-resistant obsessive–compulsive disorder treated with deep brain stimulation : a preliminary investigation
- 2024
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In: American Journal of Medical Genetics Part B. - : John Wiley & Sons. - 1552-4841 .- 1552-485X.
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Journal article (peer-reviewed)abstract
- Individuals with severe and treatment-resistant obsessive-compulsive disorder (trOCD) represent a small but severely disabled group of patients. Since trOCD cases eligible for deep brain stimulation (DBS) probably comprise the most severe end of the OCD spectrum, we hypothesize that they may be more likely to have a strong genetic contribution to their disorder. Therefore, while the worldwide population of DBS-treated cases may be small (~300), screening these individuals with modern genomic methods may accelerate gene discovery in OCD. As such, we have begun to collect DNA from trOCD cases who qualify for DBS, and here we report results from whole exome sequencing and microarray genotyping of our first five cases. All participants had previously received DBS in the bed nucleus of stria terminalis (BNST), with two patients responding to the surgery and one showing a partial response. Our analyses focused on gene-disruptive rare variants (GDRVs; rare, predicted-deleterious single-nucleotide variants or copy number variants overlapping protein-coding genes). Three of the five cases carried a GDRV, including a missense variant in the ion transporter domain of KCNB1, a deletion at 15q11.2, and a duplication at 15q26.1. The KCNB1 variant (hg19 chr20-47991077-C-T, NM_004975.3:c.1020G>A, p.Met340Ile) causes substitution of methionine for isoleucine in the trans-membrane region of neuronal potassium voltage-gated ion channel KV2.1. This KCNB1 substitution (Met340Ile) is located in a highly constrained region of the protein where other rare missense variants have previously been associated with neurodevelopmental disorders. The patient carrying the Met340Ile variant responded to DBS, which suggests that genetic factors could potentially be predictors of treatment response in DBS for OCD. In sum, we have established a protocol for recruiting and genomically characterizing trOCD cases. Preliminary results suggest that this will be an informative strategy for finding risk genes in OCD.
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| 21. |
- Chen, Tian-Jiao, et al.
(author)
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Genetic and environmental influences on the relationship between ADHD symptoms and internalizing problems : A Chinese twin study
- 2016
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In: American Journal of Medical Genetics Part B. - Hoboken, USA : John Wiley & Sons. - 1552-4841 .- 1552-485X. ; 171:7, s. 931-937
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Journal article (peer-reviewed)abstract
- Several twin studies have investigated the overlap between attention deficit hyperactivity disorder (ADHD) and externalizing problems; however, limited information is known regarding the genetic and environmental contribution to the overlap between ADHD and internalizing problems. This study examined the genetic and environmental influences on the variation in and covariation between ADHD symptoms and internalizing problems by using the Child Behavior Checklist (CBCL). We investigated 1,316 child and adolescent twins, including 780 monozygotic twins and 536 dizygotic twins, aged 6 years to 18 years from the Chinese Child and Adolescent Twin Registry. ADHD symptoms and internalizing problems were quantified through parent rating by using the Attention Problems Scale and other three scales, which include Anxious/Depressed, Withdrawn, and Somatic Complaints of CBCL. Genetic and environmental susceptibilities common to ADHD symptoms and internalizing problems were examined through bivariate twin modeling. Results showed that genetic factors substantially influenced the ADHD symptoms with a heritability of 72%. Modest genetic influences and substantial shared environmental influences (20-77%) were observed in the three internalizing problem scales. Common genetic and shared environmental influences were essential for the overlap between ADHD and the three internalizing problems respectively. Approximately one-fifth of the genetic variance of ADHD symptoms was shared with anxiety/depression. In conclusion, substantial genetic and shared environmental influences on ADHD symptoms and internalizing problems were observed in Chinese children and adolescents. Our finding supports a common etiology between ADHD and internalizing problems. This finding can also help explain the co-existence of these behavior problems. © 2015 Wiley Periodicals, Inc.
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| 22. |
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| 23. |
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| 24. |
- Durand, Christelle M, et al.
(author)
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Expression and genetic variability of PCDH11Y, a gene specific to Homo sapiens and candidate for susceptibility to psychiatric disorders.
- 2006
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In: American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics : The Official Publication of the International Society of Psychiatric Genetics. - : Wiley. - 1552-4841. ; 141:1, s. 67-70
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Journal article (peer-reviewed)abstract
- Synaptogenesis, the formation of functional synapses, is a crucial step for the development of the central nervous system. Among the genes involved in this process are cell adhesion molecules, such as protocadherins and neuroligins, which are essential factors for the identification of the appropriate partner cell and the formation of synapses. In this work, we studied the expression and the genetic variability of two closely related members of the protocadherin family PCDH11X/Y, located on the X and the Y chromosome, respectively. PCDH11Y is one of the rare genes specific to the hominoid lineage, being absent in other primates. Expression analysis indicated that transcripts of the PCDH11X/Y genes are mainly detected in the cortex of the human brain. Mutation screening of 30 individuals with autism identified two PCDH11Y polymorphic amino acid changes, F885V and K980N. These variations are in complete association, appeared during human evolution approximately 40,000 years ago and represent informative polymorphisms to study Y chromosome variability in populations. We studied the frequency of these variants in males with autism spectrum disorders (n = 110), attention deficit hyperactivity disorder (ADHD; n = 61), bipolar disorder (n = 61), obsessive-compulsive disorder (n = 51), or schizophrenia (n = 61) and observed no significant differences when compared to ethnically-matched control populations. These findings do not support the role of PCDH11Y, or more generally of a frequent specific Y chromosome, in the susceptibility to these neuropsychiatric disorders.
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| 25. |
- Ekström, Anne-Berit, 1960, et al.
(author)
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Autism spectrum conditons in myotonic dystrophy type 1: A study on 57 individuals with congenital and childhood forms
- 2008
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In: American Journal of Medical Genetics Part B: Neuropsychiatric Genetics. - : Wiley. - 1552-4841 .- 1552-485X. ; 147B:6, s. 918-926
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Journal article (peer-reviewed)abstract
- Myotonic dystrophy type 1 (DM1) is an autosomal dominant disorder, caused by an expansion of a CTG triplet repeat in the DMPK gene. The aims of the present study were to classify a cohort of children with DM1, to describe their neuropsychiatric problems and cognitive level, to estimate the size of the CTG expansion, and to correlate the molecular findings with the neuropsychiatric problems. Fifty-seven children and adolescents (26 females; 31 males) with DM1 (CTG repeats > 40) were included in the study. The following instruments were used: Autism Diagnostic Interview-Revised (ADI-R), 5-15, Griffiths Mental Development Scales, and the Wechsler Scales. Based on age at onset and presenting symptoms, the children were divided into four DM1 groups; severe congenital (n = 19), mild congenital (n = 18), childhood (n = 18), and classical DM1 (n = 2). Forty-nine percent had an autism spectrum disorder (ASD) and autistic disorder was the most common diagnosis present in 35% of the subjects. Eighty-six percent of the individuals with DM1 had mental retardation (MR), most of them moderate or severe MR. ASD was significantly correlated with the DM1 form; the more severe the form of DM1, the higher the frequency of ASD. The frequency of ASD increased with increasing CTG repeat expansions. ASD and/or other neuropsychiatric disorders such as attention deficit hyperactivity disorder, and Tourette's disorder were found in 54% of the total DM1. group. In conclusion, awareness of ASD comorbidity in DM1. is essential. Further studies are warranted to elucidate the molecular etiology causing neurodevelopmental symptoms such as ASD and MR in DM1. (c) 2008 Wiley-Liss, Inc.
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| 26. |
- Evangelou, Evangelos, et al.
(author)
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Non-replication of association for six polymorphisms from meta-analysis of genome-wide association studies of Parkinson's disease : large-scale collaborative study
- 2010
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In: American Journal of Medical Genetics, Part B: Neuropsychiatric Genetics. - : Wiley. - 1552-4841 .- 1552-485X. ; 153B:1, s. 8-220
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Journal article (peer-reviewed)abstract
- Early genome-wide association (GWA) studies on Parkinson's disease (PD) have not been able to yield conclusive, replicable signals of association, perhaps due to limited sample size. We aimed to investigate whether association signals derived from the meta-analysis of the first two GWA investigations might be replicable in different populations. We examined six single-nucleotide polymorphisms (SNPs) (rs1000291, rs1865997, rs2241743, rs2282048, rs2313982, and rs3018626) that had reached nominal significance with at least two of three different strategies proposed in a previous analysis of the original GWA studies. Investigators from the "Genetic Epidemiology of Parkinson's Disease" (GEOPD) consortium were invited to join in this study. Ten teams contributed replication data from 3,458 PD cases and 3,719 controls. The data from the two previously published GWAs (599 PD cases, 592 controls and 443 sibling pairs) were considered as well. All data were synthesized using both fixed and random effects models. The summary allelic odds ratios were ranging from 0.97 to 1.09 by random effects, when all data were included. The summary estimates of the replication data sets (excluding the original GWA data) were very close to 1.00 (range 0.98-1.09) and none of the effects were nominally statistically significant. The replication data sets had significantly different results than the GWA data. Our data do not support evidence that any of these six SNPs reflect susceptibility markers for PD. Much stronger signals of statistical significance in GWA platforms are needed to have substantial chances of replication. Specifically in PD genetics, this would require much larger GWA studies and perhaps novel analytical techniques.
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| 27. |
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| 28. |
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| 29. |
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| 30. |
- Fukumoto, Noriko, et al.
(author)
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Sexually dimorphic effect of the Val66Met polymorphism of BDNF on susceptibility to Alzheimer's disease : New data and meta-analysis
- 2010
-
In: American journal of medical genetics. Part B, Neuropsychiatric genetics. - : Wiley. - 1552-4841 .- 1552-485X. ; 153B:1, s. 235-242
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Journal article (peer-reviewed)abstract
- Conflicting results have been reported as to whether genetic variations (Val66Met and C270T) of the brain-derived neurotrophic factor gene (BDNF) confer susceptibility to Alzheimer's disease (AD). We genotyped these polymorphisms in a Japanese sample of 657 patients with AD and 525 controls, and obtained weak evidence of association for Val66Met (P = 0.063), but not for C270T. After stratification by sex, we found a significant allelic association between Val66Met and AD in women (P = 0.017), but not in men. To confirm these observations, we collected genotyping data for each sex from 16 research centers worldwide (4,711 patients and 4,537 controls in total). The meta-analysis revealed that there was a clear sex difference in the allelic association; the Met66 allele confers susceptibility to AD in women (odds ratio = 1.14, 95% CI 1.05-1.24, P = 0.002), but not in men. Our results provide evidence that the Met66 allele of BDNF has a sexually dimorphic effect on susceptibility to AD.
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| 31. |
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| 32. |
- Gong, Xiaohong, et al.
(author)
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Analysis of X chromosome inactivation in autism spectrum disorders.
- 2008
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In: American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics. - : Wiley. - 1552-485X .- 1552-4841. ; 147B:6, s. 830-835
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Journal article (peer-reviewed)abstract
- Autism spectrum disorders (ASD) are complex genetic disorders more frequently observed in males. Skewed X chromosome inactivation (XCI) is observed in heterozygous females carrying gene mutations involved in several X-linked syndromes. In this study, we aimed to estimate the role of X-linked genes in ASD susceptibility by ascertaining the XCI pattern in a sample of 543 informative mothers of children with ASD and in a sample of 163 affected girls. The XCI pattern was also determined in two control groups (144 adult females and 40 young females) with a similar age distribution to the mothers sample and affected girls sample, respectively. We observed no significant excess of skewed XCI in families with ASD. Interestingly, two mothers and one girl carrying known mutations in X-linked genes (NLGN3, ATRX, MECP2) showed highly skewed XCI, suggesting that ascertainment of XCI could reveal families with X-linked mutations. Linkage analysis was carried out in the subgroup of multiplex families with skewed XCI (> or = 80:20) and a modest increased allele sharing was obtained in the Xq27-Xq28 region, with a peak Z-score of 1.75 close to rs719489. In summary, our results suggest that there is no major X-linked gene subject to XCI and expressed in blood cells conferring susceptibility to ASD. However, the possibility that rare mutations in X-linked genes could contribute to ASD cannot be excluded. We propose that the XCI profile could be a useful criteria to prioritize families for mutation screening of X-linked candidate genes.
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- Håkansson, Anna, 1978, et al.
(author)
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Cyclooxygenase-2 polymorphisms in Parkinson's disease.
- 2007
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In: American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics. - : Wiley. - 1552-4841. ; 144:3, s. 367-9
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Journal article (peer-reviewed)abstract
- Accumulating evidence indicate that cyclooxygenase-2 (COX-2) is of pathophysiological importance for the neurodegeneration in Parkinson's disease (PD). For example, in a large epidemiological study, use of NSAIDs was associated with a lower risk of PD. Genetic variants of the COX-2 gene might therefore influence the risk of developing the disease. The genotype distribution of four common single nucleotide polymorphisms (SNPs) in the COX-2 gene (rs689466:A496G, rs20417:G926C, rs5277:G3050C, rs5275:C8473T) was analyzed in PD patients and control subjects in a Swedish population. No differences could be seen between the PD-patient and controls regarding the A496G, G926C, and G3050C SNPs, but the allele frequency of the C8473T SNP was found to differ when male patients were compared to controls (P = 0.007). In females no difference could be seen between PD-patients and controls. In conclusion, the results suggest a possible influence of the COX-2 C8473T SNP in PD, although it only seems to be of importance in men.
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| 41. |
- Håkansson, Anna, 1978, et al.
(author)
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Interaction of polymorphisms in the genes encoding interleukin-6 and estrogen receptor beta on the susceptibility to Parkinson's disease.
- 2005
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In: American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics. - : Wiley. - 1552-4841 .- 1552-485X. ; 133:1, s. 88-92
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Journal article (peer-reviewed)abstract
- The multifunctional cytokine interleukin-6 (IL-6) is involved in inflammatory processes in the central nervous system and increased levels of IL-6 have been found in patients with Parkinson's disease (PD). It is known that estrogen inhibits the production of IL-6, via action on estrogen receptors, thereby pointing to an important influence of estrogen on IL-6. In a previous study, we reported an association between a G/A single nucleotide polymorphism (SNP) at position 1730 in the gene coding for estrogen receptor beta (ERbeta) and age of onset of PD. To investigate the influence of a G/C SNP at position 174 in the promoter of the IL-6 gene, and the possible interaction of this SNP and the ERbeta G-1730A SNP on the risk for PD, the G-174C SNP was genotyped, by pyrosequencing, in 258 patients with PD and 308 controls. A significantly elevated frequency of the GG genotype of the IL-6 SNP was found in the patient group and this was most obvious among patients with an early age of onset (
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| 42. |
- Johansson Capusan, Andrea, et al.
(author)
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Genetic and environmental contributions to the association between attention deficit hyperactivity disorder and alcohol dependence in adulthood : A large population-based twin study
- 2015
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In: American Journal of Medical Genetics Part B. - Hoboken, USA : Wiley-Blackwell. - 1552-4841 .- 1552-485X. ; 168:6, s. 414-422
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Journal article (peer-reviewed)abstract
- Previous research indicates that attention deficit hyperactivity disorder (ADHD) frequently co-occurs with alcohol dependence; however, the extent to which shared genetic risk factors underpin this association remains unclear. The aim of this study is to investigate the relative importance of genetic, shared, and nonshared environmental factors for the overlap between ADHD and alcohol dependence in adults. Almost 18,000 adult twins aged 20-45 years, from more than 12,000 twin pairs (5,420 complete pairs), from the population-representative Swedish Twin Registry, were included. Self-ratings were used to assess symptoms of ADHD and alcohol dependence. Twin analysis was used to determine the role of additive genetic (A), shared (C), and nonshared environmental (E) factors. As a result, we found a significant association between ADHD and alcohol dependence (odds ratio 3.58; 95% confidence interval, 2.85-4.49). Twin analysis suggested that shared genetic risk factors explained 64% of the overlap between ADHD and alcohol dependence. Nonshared environmental factors accounted for the remaining 36%, whereas the contribution of shared environmental factors was minimal. We found no support for statistically significant sex differences in the overlap between ADHD and alcohol dependence. In conclusion the overlap between ADHD and alcohol dependence in adulthood was largely explained by shared genetic risk factors. This is an important step toward understanding the underlying nature of the risk of alcohol dependence in patients with ADHD and suggests that individuals with ADHD and their family members are important targets for alcohol prevention and treatment.
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| 43. |
- Johansson, S, et al.
(author)
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Genetic analyses of dopamine related genes in adult ADHD patients suggest an association with the DRD5-microsatellite repeat, but not with DRD4 or SLC6A3 VNTRs.
- 2008
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In: American journal of medical genetics. Part B, Neuropsychiatric genetics. - : Wiley. - 1552-485X .- 1552-4841. ; 147B:8, s. 1470-1475
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Journal article (peer-reviewed)abstract
- Attention deficit hyperactivity disorder (ADHD) is a common and highly heritable psychiatric disorder in children and adults. Recent meta-analyses have indicated an association between genes involved in dopaminergic signaling and childhood ADHD, but little is known about their possible role in adult ADHD. In this study of adults with ADHD, we evaluated the three most commonly studied ADHD candidate genetic polymorphisms; the dopamine receptor D4 (DRD4) exon 3 VNTR repeat, a microsatellite repeat 18.5 kb upstream of the DRD5 locus and the 3'UTR dopamine transporter SLC6A3 (DAT 1) VNTR. We examined 358 clinically diagnosed adult Norwegian ADHD patients (51% males) and 340 ethnically matched controls. We found a nominally significant overall association with adult ADHD for the DRD5 microsatellite marker (P = 0.04), and a trend toward increased risk associated with the 148-bp allele consistent with recent meta-analyses. The strongest overall association (P = 0.02) and increased risk for the 148-bp allele [odds ratio (OR) = 1.27 (95% CI: 1.00-1.61)] were seen in the inattentive and combined inattentive/hyperactive group as previously reported for childhood ADHD. No association was found for the DRD4 or SLC6A3 polymorphisms in this patient sample. In conclusion, our results among adults with a clinical diagnosis of ADHD support an association between ADHD and the DRD5 locus, but not the DRD4 or SLC6A3 loci. It is possible that the latter polymorphisms are associated with a transient form of ADHD with better long-term clinical outcome. (c) 2007 Wiley-Liss, Inc.
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- Jönsson, Erik G., et al.
(author)
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Two methylenetetrahydrofolate reductase gene (MTHFR) polymorphisms, schizophrenia and bipolar disorder : An association study
- 2008
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In: American journal of medical genetics. Part B, Neuropsychiatric genetics. - : Wiley. - 1552-4841. ; 147B:6, s. 976-982
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Journal article (peer-reviewed)abstract
- Recent meta-analyses of the methylenetetrahydrofolate reductase gene (MTHFR) have suggested association between two of its functional single gene polymorphisms (SNPs, C677T and A1298C) and schizophrenia. Studies have also suggested association between MTHFR C677T and A1298C variation and bipolar disorder. In a replication attempt the MTHFR C677T and A1298C SNPs were analyzed in three Scandinavian schizophrenia case-control samples. In addition, Norwegian patients with bipolar disorder were investigated. There were no statistically significant allele or genotype case-control differences. The present Scandinavian results do not verify previous associations between the putative functional MTHFR gene polymorphisms and schizophrenia or bipolar disorder. However, when combined with previous studies in meta-analyses there is still evidence for association between the MTHFR C677T polymorphism. and schizophrenia. Additional studies are warranted to shed further light on these relationships. (c) 2007 Wiley-Liss, Inc.
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