DNA markers in low-IQ autism suggest heredity

A possible biomarker

Eric Morrow, lead author Ece Gamsiz, and colleagues analyzed the DNA of 2,100 autistic children in families where neither parents nor siblings were affected. Autistic children with significant intellectual disability had long “runs of homozygosity” — strands of identical DNA from both parents. Credit: Mike Cohea/Brown University

Researchers who compared the DNA of patients with autism and intellectual disability to that of their unaffected siblings found that the affected siblings had significantly more “runs of homozygosity,” or blocks of DNA that are the same from both parents. The finding suggests a role for recessive inheritance in this autism subgroup and highlights homozygosity as a new approach to understanding genetic mechanisms in autism.