A study published in JAMA (2014) investigated the familial risk of autism spectrum disorders (ASD) and autistic disorder (AD) in a large Swedish population-based cohort of children born between 1982 and 2007. The study found that ASD has a heritability of approximately 50%, with genetic factors explaining half of the liability for the disorder. The relative recurrence risk (RR) for ASD was significantly higher for close family members, with a 10-fold increase if a full sibling has the diagnosis and a 2-fold increase if a cousin has the diagnosis. The RR was also higher for AD, though to a slightly lesser extent. The study estimated that genetic factors, particularly additive genetic effects, and non-shared environmental factors contributed to the risk of ASD and AD. Shared environmental factors had a minimal impact. The study also found that the risk of ASD was not significantly affected by the sex of the offspring or the sex of the proband. The findings suggest that genetic factors play a major role in the development of ASD and AD, and that family counseling should consider these risks. The study used a longitudinal cohort design and adjusted for various confounding factors, including parental psychiatric history, parental age, and birth cohort. The results provide valuable insights into the genetic and environmental influences on ASD and AD, and may inform counseling for families with affected children.A study published in JAMA (2014) investigated the familial risk of autism spectrum disorders (ASD) and autistic disorder (AD) in a large Swedish population-based cohort of children born between 1982 and 2007. The study found that ASD has a heritability of approximately 50%, with genetic factors explaining half of the liability for the disorder. The relative recurrence risk (RR) for ASD was significantly higher for close family members, with a 10-fold increase if a full sibling has the diagnosis and a 2-fold increase if a cousin has the diagnosis. The RR was also higher for AD, though to a slightly lesser extent. The study estimated that genetic factors, particularly additive genetic effects, and non-shared environmental factors contributed to the risk of ASD and AD. Shared environmental factors had a minimal impact. The study also found that the risk of ASD was not significantly affected by the sex of the offspring or the sex of the proband. The findings suggest that genetic factors play a major role in the development of ASD and AD, and that family counseling should consider these risks. The study used a longitudinal cohort design and adjusted for various confounding factors, including parental psychiatric history, parental age, and birth cohort. The results provide valuable insights into the genetic and environmental influences on ASD and AD, and may inform counseling for families with affected children.