| 1. |
- Garcia, Danilo, 1973, et al.
(author)
-
Temperament and Character in the Child and Adolescent Twin Study in Sweden (CATSS): Comparison to the General Population, and Genetic Structure Analysis
- 2013
-
In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:8
-
Journal article (peer-reviewed)abstract
- Background The Child and Adolescent Twin Study in Sweden (CATSS) is an on-going, large population-based longitudinal twin study. We aimed (1) to investigate the reliability of two different versions (125-items and 238-items) of Cloninger's Temperament and Character Inventory (TCI) used in the CATSS and the validity of extracting the short version from the long version, (2) to compare these personality dimensions between twins and adolescents from the general population, and (3) to investigate the genetic structure of Cloninger's model. Method Reliability and correlation analyses were conducted for both TCI versions, 2,714 CATSS-twins were compared to 631 adolescents from the general population, and the genetic structure was investigated through univariate genetic analyses, using a model-fitting approach with structural equation-modeling techniques based on same-sex twin pairs from the CATSS (423 monozygotic and 408 dizygotic pairs). Results The TCI scores from the short and long versions showed comparable reliability coefficients and were strongly correlated. Twins scored about half a standard deviation higher in the character scales. Three of the four temperament dimensions (Novelty Seeking, Harm Avoidance, and Persistence) had strong genetic and non-shared environmental effects, while Reward Dependence and the three character dimensions had moderate genetic effects, and both shared and non-shared environmental effects. Conclusions Twins showed higher scores in character dimensions compared to adolescents from the general population. At least among adolescents there is a shared environmental influence for all of the character dimensions, but only for one of the temperament dimensions (i.e., Reward Dependence). This specific finding regarding the existence of shared environmental factors behind the character dimensions in adolescence, together with earlier findings showing a small shared environmental effects on character among young adults and no shared environmental effects on character among adults, suggest that there is a shift in type of environmental influence from adolescence to adulthood regarding character.
|
|
| 2. |
- Karlsson, Louise, et al.
(author)
-
The SWedish Eating Assessment for Autism spectrum disorders (SWEAA)-Validation of a self-report questionnaire targeting eating disturbances within the autism spectrum.
- 2013
-
In: Research in developmental disabilities. - : Elsevier BV. - 1873-3379 .- 0891-4222. ; 34:7, s. 2224-33
-
Journal article (peer-reviewed)abstract
- The aim was to design and validate a questionnaire pertaining to eating problems in individuals with normal intelligence, within the autism spectrum. The questionnaire was based on literature search and clinical experience. The validation focused on psychometric properties of reliability and validity using a clinical group of individuals with autism spectrum disorders (ASD) (n=57) and a matched, healthy comparison group (n=31). The instrument showed high levels of reliability, convergent and discriminant validity and scaling properties. Logistic regression analyses discerned the single item Simultaneous capacity and the subscale Social situation at mealtime as the best predictors of ASD. In conclusion, the questionnaire is valid and reliable to detect disturbed eating behaviours in individuals with ASD and normal intelligence.
|
|
| 3. |
|
|
| 4. |
- Larson, Tomas, et al.
(author)
-
Predictive properties of the A-TAC inventory when screening for childhood-onset neurodevelopmental problems in a population-based sample
- 2013
-
In: BMC Psychiatry. - 1471-244X. ; 13
-
Journal article (peer-reviewed)abstract
- Background: Identifying children with childhood-onset neurodevelopmental problems (NDPs, defined here as autism spectrum disorders [ASDs], attention-deficit/hyperactivity disorder [AD/HD], tic disorders [TDs], learning disorders [LDs] and development coordination disorder), using easily administered screening instruments, is a prerequisite for epidemiological research. Such instruments are also clinically useful to prioritize children for comprehensive assessments, to screen risk groups, and to follow controls. Autism-Tics, ADHD, and other Co-morbidities inventory (A-TAC) was developed to meet these requirements; here the A-TAC's prospective and psychometric properties are examined, when used in a population-based, epidemiological setting. Methods: Since 2004, parents of all Swedish twins have been asked to take part in an ongoing, nation-wide twin study (The Child and Adolescent Twin Study in Sweden). The study includes the A-TAC, carried out as a telephone interview with parents of twins aged 9 or 12. In the present study, screen-positive twins from three birth year cohorts (1993-1995) were invited to a comprehensive clinical follow-up (blinded for previous screening results) together with their co-twins and randomly selected, healthy controls at age 15 (Total N = 452). Results: Sensitivity and specificity of A-TAC scores for predicting later clinical diagnoses were good to excellent overall, with values of the area under the receiver operating characteristics curves ranging from 0.77 (AD/HD) to 0.91 (ASDs). Among children who were screen-positive for an ASD, 48% received a clinical diagnosis of ASDs. For AD/HD, the corresponding figure was also 48%, for LDs 16%, and for TDs 60%. Between 4% and 35% of screen-positive children did not receive any diagnosis at the clinical follow-up three years later. Among screen-negative controls, prevalence of ASDs, AD/HD, LDs, and TDs was 0%, 7%, 4%, and 2%, respectively. Conclusions: The A-TAC appeared to be a valid instrument to assess NDPs in this population-based, longitudinal study. It has good-to-excellent psychometric properties, with an excellent ability to distinguish NDPs (mainly ASDs) from non-NDPs at least three years after the screening evaluations, although specific diagnoses did not correspond closely to actual clinical diagnoses.
|
|
| 5. |
- Magnusson, Patrik K. E., et al.
(author)
-
The Swedish Twin Registry : establishment of a biobank and other recent developments
- 2013
-
In: Twin Research and Human Genetics. - Cambridge, United Kingdom : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 16:1, s. 317-329
-
Journal article (peer-reviewed)abstract
- The Swedish Twin Registry (STR) today contains more than 194,000 twins and more than 75,000 pairs have zygosity determined by an intra-pair similarity algorithm, DNA, or by being of opposite sex. Of these, approximately 20,000, 25,000, and 30,000 pairs are monozygotic, same-sex dizygotic, and opposite-sex dizygotic pairs, respectively. Since its establishment in the late 1950s, the STR has been an important epidemiological resource for the study of genetic and environmental influences on a multitude of traits, behaviors, and diseases. Following large investments in the collection of biological specimens in the past 10 years we have now established a Swedish twin biobank with DNA from 45,000 twins and blood serum from 15,000 twins, which effectively has also transformed the registry into a powerful resource for molecular studies. We here describe the main projects within which the new collections of both biological samples as well as phenotypic measures have been collected. Coverage by year of birth, zygosity determination, ethnic heterogeneity, and influences of in vitro fertilization are also described.
|
|
| 6. |
- Råstam, Maria, et al.
(author)
-
ASD, Eating Problems, and Overlap with Anorexia and Bulimia Nervosa
- 2013
-
In: Comprehensive Guide to autism. - New York, NY : Springer New York. - 9781461447887 - 9781461447870 ; , s. 2015-2034
-
Book chapter (peer-reviewed)abstract
- Abnormal eating behaviors are overrepresented in the autism spectrum disorders, including food refusal, pica, rumination, and selective eating. Those disturbances can have detrimental complications and are often resistant to treatment. In autism spectrum disorders the background factors to eating disturbances are more complex than in the general child population, and sensory abnormalities, ritualistic behaviors, and social communication problems all seem to contribute. The eating problems in autism spectrum disorders may increase the risk for developing clinically significant eating disorders such as anorexia nervosa. Autistic traits must be considered in the treatment of the eating disorders and seem to be predictors for a poor psychosocial outcome after recovery from the eating disorder per se.
|
|
| 7. |
- Råstam, Maria, 1948, et al.
(author)
-
Eating Problems and Overlap with ADHD and Autism Spectrum Disorders in a Nationwide Twin Study of 9- and 12-Year-Old Children.
- 2013
-
In: Scientific World Journal. - : Hindawi Limited. - 1537-744X .- 2356-6140.
-
Journal article (peer-reviewed)abstract
- Aim. To establish the prevalence of restrictive eating problems, the overlap and association with attention-deficit/hyperactivity disorder (ADHD), and autism spectrum disorders (ASD) and to estimate the heritability of eating problems in a general population sample of twins aged 9 and 12. Methods. Parents of all Swedish 9- and 12-year-old twin pairs born between 1993 and 1998 (n = 12,366) were interviewed regarding symptoms of ADHD, ASD, and eating problems (EAT-P). Intraclass correlations and structural equation modelling were used for evaluating the influence of genetic and environmental factors. Cross-twin, cross-trait correlations were used to indicate a possible overlap between conditions. Results. The prevalence of eating problems was 0.6% in the study population and was significantly higher in children with ADHD and/or ASD. Among children with eating problems, 40% were screened positive for ADHD and/or ASD. Social interaction problems were strongly associated with EAT-P in girls, and impulsivity and activity problems with EAT-P in boys. The cross-twin, cross-trait correlations suggested low correlations between EAT-P and ADHD or EAT-P and ASD. Genetic effects accounted for 44% of the variation in liability for eating problems. Conclusions. In the group with eating problems, there was a clear overrepresentation of individuals with ADHD and/or ASD symptoms.
|
|
| 8. |
- Scheid, Isabelle, et al.
(author)
-
Heterozygous FA2H mutations in autism spectrum disorders
- 2013
-
In: BMC Medical Genetics. - : Springer Science and Business Media LLC. - 1471-2350. ; 14
-
Journal article (peer-reviewed)abstract
- Background Widespread abnormalities in white matter development are frequently reported in cases of autism spectrum disorders (ASD) and could be involved in the disconnectivity suggested in these disorders. Homozygous mutations in the gene coding for fatty-acid 2-hydroxylase (FA2H), an enzyme involved in myelin synthesis, are associated with complex leukodystrophies, but little is known about the functional impact of heterozygous FA2H mutations. We hypothesized that rare deleterious heterozygous mutations of FA2H might constitute risk factors for ASD. Methods We searched deleterious mutations affecting FA2H, by genotyping 1256 independent patients with ASD genotyped using Genome Wide SNP arrays, and also by sequencing in independent set of 186 subjects with ASD and 353 controls. We then explored the impact of the identified mutations by measuring FA2H enzymatic activity and expression, in transfected COS7 cells. Results One heterozygous deletion within 16q22.3-q23.1 including FA2H was observed in two siblings who share symptoms of autism and severe cognitive impairment, axial T2-FLAIR weighted MRI posterior periventricular white matter lesions. Also, two rare non-synonymous mutations (R113W and R113Q) were reported. Although predictive models suggested that R113W should be a deleterious, we did not find that FA2H activity was affected by expression of the R113W mutation in cultured COS cells. Conclusions While our results do not support a major role for FA2H coding variants in ASD, a screening of other genes related to myelin synthesis would allow us to better understand the role of non-neuronal elements in ASD susceptibility.
|
|
