{"id":1678,"date":"2024-11-26T15:34:50","date_gmt":"2024-11-26T14:34:50","guid":{"rendered":"https:\/\/fondation-autisme.org\/influence-de-la-genetique\/"},"modified":"2025-09-26T23:27:28","modified_gmt":"2025-09-26T21:27:28","slug":"genetic-factors","status":"publish","type":"post","link":"https:\/\/fondation-autisme.org\/en\/genetic-factors\/","title":{"rendered":"Genetic factors"},"content":{"rendered":"

Certain forms of autism have an entirely genetic origin. This is the case with Fragile X syndrome, Angelman syndrome, and Rett syndrome. These purely genetic syndromes are not the focus of this page.<\/p>\n

In general, a genetic predisposition appears to be linked to the development of autism spectrum disorders<\/b>, as suggested by the following research findings:<\/p>\n

    <\/ol>\n
      \n
    1. \n

      The prevalence of autism in the general population appears to be approximately 1%.<\/p>\n<\/li>\n

    2. \n

      In families where one child is autistic, siblings have a 10% chance of also being diagnosed. This percentage rises to 20% when language delay is included.
      Reference: Sibling Recurrence and the Genetic Epidemiology of Autism, Constantino, Zhang, Frazier et al. Am J Psychiatry 2010; 167, 1349-1356<\/i><\/span><\/p>\n<\/li>\n

    3. \n

      In families where one fraternal (dizygotic) twin is autistic, the other has a 20% chance of also being diagnosed. This percentage increases when bipolar disorders are taken into account<\/p>\n<\/li>\n

    4. \n

      In families where one identical (monozygotic) twin is autistic, the other has about a 90% chance of also being diagnosed.<\/p>\n

      Reference : Rosenberg, Law, Yenokyan et al. Arch Pediatr Adolesc Med. 2009;163(10):907-914<\/i><\/p>\n<\/li>\n

    5. \n

      Finally, a 2014 Swedish study found inherited genetic anomalies in 52% of cases within a cohort of individuals with autism, with fewer than 3% involving de novo mutations.<\/p>\n

      <\/i><\/p>\n

      Reference : Gaugler, T., Klei, L., Sanders, S. et al. Most genetic risk for autism resides with common variation. Nat Genet 46, 881\u2013885 (2014). <\/i><\/p>\n<\/li>\n<\/ol>\n<\/div><\/div><\/div>

      <\/span><\/div>
      \n

      For families<\/b><\/p>\n

      While genetics undeniably play a role, they alone cannot account for the rise in prevalence. Environmental factors also have a significant impact. Autism in your family is therefore not an inevitable fate for future generations.<\/p>\n<\/blockquote>\n<\/div><\/div><\/div>

      First conclusion: while it cannot explain the current rise in autism spectrum disorders, genetics does play an important role in their onset.<\/b><\/p>\n

      In the 2024 study monitoring the All Babies in Southeast Sweden (ABIS) cohort, the authors report a correlation between the emergence of neurodevelopmental disorders and specific configurations of the HLA system, the genetically inherited part of the immune system.
      Reference : Ahrens et al., 2024, Cell 187, 1853\u20131873 April 11, 2024 Published by Elsevier<\/i><\/p>\n

      Second conclusion: the link between genetics and autism spectrum disorders appears to involve, at least in part, a vulnerability of the immune system.<\/b><\/p>\n<\/div><\/div><\/div><\/div><\/div>

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