| 31. |
- Van Schijndel, Jessica E., et al.
(författare)
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Dual association of a TRKA polymorphism with schizophrenia
- 2011
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Ingår i: Psychiatric Genetics. - : Lippincott Williams & Wilkins. - 0955-8829 .- 1473-5873. ; 21:3, s. 125-131
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: An interaction between predisposing genes and environmental stressors is thought to underlie the neurodevelopmental disorder schizophrenia. In a targeted gene screening, we previously found that the minor allele of the single nucleotide polymorphism (SNP) rs6336 in the neurotrophic tyrosine kinase receptor 1 (NTRK1/TRKA) gene is associated with schizophrenia as a risk factor.METHODS: We genotyped the TRKA SNP in a total of eight independent Caucasian schizophrenia case-control groups.RESULT: Remarkably, although in five of the groups a higher frequency of the risk allele was indeed found in the patients compared with the controls, in the three other groups the SNP acted as a protective factor.CONCLUSION: An intriguing possibility is that this dual character of the TRKA SNP is caused by its interaction with endophenotypic and/or epistatic factors.
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| 32. |
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| 33. |
- Visscher, Peter M., et al.
(författare)
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Genetic survival analysis of age-at-onset of bipolar disorder : evidence for anticipation or cohort effect in families
- 2001
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Ingår i: Psychiatric Genetics. - : Lippincott Williams & Wilkins. - 0955-8829 .- 1473-5873. ; 11:3, s. 129-137
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Tidskriftsartikel (refereegranskat)abstract
- Age-at-onset (AAO) in a number of extended families ascertained for bipolar disorder was analysed using survival analysis techniques, fitting proportional hazards models to estimate the fixed effects of sex, year of birth, and generation, and a random polygenic genetic effect. Data comprised the AAO (for 171 affecteds) or age when last seen (ALS) for 327 unaffecteds, on 498 individuals in 27 families. ALS was treated as the censored time in the statistical analyses. The majority of individuals classified as affected were diagnosed with bipolar I and II (n = 103) or recurrent major depressive disorder (n = 68). In addition to the significant effects of sex and year of birth, a fitted ‘generation’ effect was highly significant, which could be interpreted as evidence for an anticipation effect. The risk of developing bipolar or unipolar disorder increased twofold with each generation descended from the oldest founder. However, although information from both affected and unaffected individuals was used to estimate the relative risk of subsequent generations, it is possible that the results are biased because of the ‘Penrose effect’. Females had a twofold increased risk in developing depressive disorder relative to males. The risk of developing bipolar or unipolar disorder increased by approximately 4% per year of birth. A polygenic component of variance was estimated, resulting in a ‘heritability’ of AAO of approximately 0.52. In a family showing strong evidence of linkage to chromosome 4p (family 22), the ‘affected haplotype’ increased the relative risk of being affected by a factor of 46. In this family, there was strong evidence of a time trend in the AAO. When either year of birth or generation was fitted in the model, these effects were highly significant, but neither was significant in the presence of the other. For this family, there was no increase in trinucleotide repeats measured by the repeat expansion detection method in affected individuals compared with control subjects. Proportional hazard models appear appropriate to analyse AAO data, and the methodology will be extended to map quantitative trait loci (QTL) for AAO.
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| 34. |
- Wargelius, Hanna-Linn, et al.
(författare)
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Associations of MAOA-VNTR or 5HTT-LPR alleles with attention-deficit hyperactivity disorder symptoms are moderated by platelet monoamine oxidase B activity
- 2012
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Ingår i: Psychiatric Genetics. - 0955-8829 .- 1473-5873. ; 22:1, s. 42-45
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Tidskriftsartikel (refereegranskat)abstract
- The monoamine systems have been suggested to play a role in the biological basis of ADHD symptoms. Thus, polymorphisms in e.g. the monoamine oxidase A (MAOA) and the serotonin transporter (5HTT) genes have been associated with ADHD like phenotypes. Furthermore, platelet MAOB activity has frequently been linked to impulsiveness-related traits. In the present paper, we have studied ADHD symptoms with regard to the combination of platelet MAOB activity and MAOAVNTR or 5HTT-LPR genotype. The study group consisted of 156 adolescent twin pairs, i.e. 312 individuals, who were used in a previous study (Malmberg et al., 2008). ADHD symptoms were scored with a structured clinical interview of both the twin and a parent using Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version. Presence of a short 5HTT-LPR or short MAOA-VNTR allele, in combination with high levels of platelet MAOB enzyme activity was associated with higher scores of ADHD like problems (p<0.001; p<0.01, respectively). This reexamination of ADHD scores in a non-clinical sample suggests that effects of the MAOA-VNTR and 5HTT-LPR are moderated by platelet MAOB activity.
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