Associations Among Sex, Cognitive Ability, and Autism Symptoms in Individuals with Down Syndrome.

Only participants who could produce multi-word utterances were included, so results do not apply to minimally verbal or more severely impaired people with Down syndrome. Autism symptoms were assessed with ADOS-2 only, without full developmental history or DSM-5 diagnostic evaluation, so autism classification may not match a comprehensive diagnosis. Participants ranged from 6 to 23 years, while ADOS-2 severity norms end at 14 years for Module 1 and 16 years for Modules 2 and 3; older participants used the upper age limits, limiting interpretation. A few Module 1 participants produced only single words during assessment despite caregiver reports of multi-word phrases, showing imperfect screening. The sample was drawn from a larger expressive language project and recruited through clinics, community events, referrals, advertisements, internet postings, past research, and university registries, so it may not represent all people with Down syndrome. Five participants were excluded for missing Stanford-Binet data, and the verbal IQ measure combines broad abilities that may not reflect everyday communication.

Funded by National Institute of Health (US), Eunice Kennedy Shriver National Institute of Child Health and Human Development, and National Center for Advancing Translational Sciences. The text does not report author conflicts of interest.

Do not conclude that autism symptoms are equally common in all people with Down syndrome regardless of sex. The study included only verbal participants who could produce multi-word utterances, and the sex difference in autism classification was not significant.