To the Editor The recent report by Dr Sandin and colleagues1 contributes to a converging body of recent research specifying recurrence rates in autism spectrum disorders (ASD) by analyzing data from a large epidemiological birth cohort in Sweden.
The results included a large-scale confirmation that the sex of the proband does not predict familial recurrence risk, indicating that the Carter effect (increased familial recurrence among subsets of cases [eg, females] who have been hypothesized to require higher than usual genetic loading to express the disorder), which was observed for subclinical autistic-like traits in a sample from the United Kingdom and Sweden,2 may not apply to a majority of clinical autistic syndromes.
Constantino JN. Recurrence Rates in Autism Spectrum Disorders. JAMA. 2014;312(11):1154-1155. doi:10.1001/jama.2014.9841