Autism as a Strongly Genetic Disorder: Evidence from a British Twin Study

MRC Child Psychiatry Unit, Institute of Psychiatry, London.
Psychological Medicine (Impact Factor: 5.94). 02/1995; 25(1):63-77. DOI: 10.1017/S0033291700028099
Source: PubMed


Two previous epidemiological studies of autistic twins suggested that autism was predominantly genetically determined, although the findings with regard to a broader phenotype of cognitive, and possibly social, abnormalities were contradictory. Obstetric and perinatal hazards were also invoked as environmentally determined aetiological factors. The first British twin sample has been re-examined and a second total population sample of autistic twins recruited. In the combined sample 60% of monozygotic (MZ) pairs were concordant for autism versus no dizygotic (DZ) pairs; 92% of MZ pairs were concordant for a broader spectrum of related cognitive or social abnormalities versus 10% of DZ pairs. The findings indicate that autism is under a high degree of genetic control and suggest the involvement of multiple genetic loci. Obstetric hazards usually appear to be consequences of genetically influenced abnormal development, rather than independent aetiological factors. Few new cases had possible medical aetiologies, refuting claims that recognized disorders are common aetiological influences.

554 Reads
    • "The prevalence is considered to be 0.6–1.1 % (Levy et al. 2009; Baird et al. 2006; Hirtz et al. 2007) with a male:female ratio of 3–4:1 (Volkmar et al. 2004; Abrahams et al. 2007; Lai et al. 2015). According to multiple family and twin studies reporting a substantial heritable component ranging between 70 and 90 % of autism etiology (Bailey et al. 1995; Freitag 2011; Folstein and Rosen-Sheidley 2001), ASD is considered to be one of the most strongly genetically influenced multifactorial childhood psychiatric disorders (Hallmayer et al. 2011). Despite the high heritability, the genetics are inferred to be complex and no major gene has been identified to be relevant for the majority of ASD diagnoses (Freitag et al. 2010). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The Contactin Associated Protein-like 2 (CNTNAP2) gene has been discussed to be associated with different symptoms of autism spectrum disorders (ASDs) and other neurodevelopmental disorders. We aimed to elucidate the genetic association of CNTNAP2 within high functioning ASD (HFA), focusing on autism specific symptoms and reducing intelligence related factors. Furthermore, we compared our findings conducting a meta-analysis in patients with ASD and HFA only. A case-control association study was performed for HFA (HFA, n = 105; controls, n = 133). Moreover, we performed a family-based association study (DFAM) analysis (HFA, n = 44; siblings, n = 57). Individuals were genotyped for the two most frequently reported single nucleotide polymorphisms (SNPs) in the CNTNAP2 gene (rs2710102, rs7794745). Furthermore, a meta-analysis using the MIX2 software integrated our results with previously published data. A significant association for the carriers of the T-allele of the rs7794745 with HFA was found in the case-control sample [OR = 1.547; (95 % CI 1.056-2.266); p = 0.025]. No association could be found by DFAM with any of the CNTNAP2 SNPs with HFA. The meta-analysis of both SNPs did not show a significant association with either ASD or with HFA. Overall, including case-control, sibs, and meta-analysis, we could not detect any significant association with the CNTNAP2 gene and HFA. Our results point in the direction that CNTNAP2 may not play a major role in HFA, but rather seems to have a significance in neurodevelopmental disorders or in individuals displaying intellectual delays.
    Journal of Neural Transmission 11/2015; DOI:10.1007/s00702-015-1458-5 · 2.40 Impact Factor
    • "The diagnostic assessment for autism requires an elaborate screening process, which involves substantial consultations with many specialists and other physicians (Myers and Johnson 2007). The global prevalence of autism is estimated to be one in 160 people, and many studies have reported that the combination of genetic and environmental factors implicate a strong association in some aspects of ASD (Bailey et al. 1995; Campbell et al. 2006; Elsabbagh et al. 2012; Hallmayer et al. 2011); however, the development of ASD continues to be largely unclear. "

    10/2015; 2:374-401. DOI:10.1007/s40489-015-0059-4
  • Source
    • "It is now well known that ASD has a strong genetic component and that relatives of ASD are at a higher risk for the disorder. Twin and family studies conducted by many research groups have indicated hereditary factors in ASD (Bailey et al., 1995; Bolton et al., 1994; Folstein and Rutter, 1977; Piven et al., 1997a). The core features of ASD that are also present in other family members of individuals with ASD, albeit in much milder forms, but not meeting diagnostic criteria for ASD, is called the ''Broad Autism Phenotype'' (BAP). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The Broad Autism Phenotype Questionnaire (BAPQ) which is a reliable, efficient and easy to administer instrument is used to assess the Broad Autism Phenotype (BAP). In order to understand cross cultural perspectives using this instrument, a key process is translation of the instrument. The process of translation is often overlooked and hence the quality of the translated instrument may suffer. This paper highlights the robust process adopted for translating the BAPQ into one of the Indian languages - Kannada, using the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) and World Health Organisation (WHO) guidelines. The translated instrument was tested on a pilot sample of parents of 10 children with ASD and parents of 11 typically developing children. The results are in congruence with the published literature. Copyright © 2015 Elsevier B.V. All rights reserved.
    Asian Journal of Psychiatry 05/2015; 15. DOI:10.1016/j.ajp.2015.04.013
Show more

Similar Publications


554 Reads
Available from
Sep 17, 2014