Familial Recurrence Rate of Autism Spectrum Disorder 20.2 Percent

Male infant sex and having more than one older affected sibling were significant predictors of familial recurrence

By Elana Gotkine HealthDay Reporter

WEDNESDAY, July 17, 2024 (HealthDay News) — The familial recurrence rate of autism spectrum disorder (ASD) is 20.2 percent, which has not changed significantly from previous estimates, according to a study published online July 16 in Pediatrics.

Sally Ozonoff, Ph.D., from the University of California Davis Health in Sacramento, and colleagues collated data across 18 sites of the Baby Siblings Research Consortium to update estimates of familial ASD recurrence. A total of 1,605 infants with an older sibling with autism were followed from early in life to age 3 years, at which point they were classified as ASD or non-ASD.

The researchers found that 20.2 percent of siblings developed ASD, which is not significantly different from the previously reported rate (18.7 percent). Significant predictors of familial recurrence included male infant sex and more than one older affected sibling. Recurrence rates were also influenced by proband sex, with the likelihood of developing ASD significantly higher for siblings of female probands than siblings of male probands. Associations were also seen for race and maternal education with recurrence in families.

“The current study reinforces the importance of developmental surveillance and screening for younger siblings of autistic children, particularly those who are male, have an affected female sibling, or have multiple affected siblings,” the authors write.

Several authors disclosed ties to the pharmaceutical and publishing industries.