Social behavior and characteristics of autism spectrum disorder in Angelman, Cornelia de Lange, and Cri du Chat syndromes.

Greer et al. (2013) looked at the kids with three rare genetic syndromes: Angelman, Cornelia de Lange, and Cri du Chat.

They gave each child the Autism Diagnostic Observation Schedule and a social-motive checklist.

The goal was to see who hit ASD cutoffs and how each group really acted around people.

Angelman and Cornelia de Lange groups passed ASD screening more often than Cri du Chat kids.

Yet each syndrome showed its own social style: Angelman kids laughed and hugged, Cornelia de Lange kids stayed close but quiet, Cri du Chat kids tried hard to talk.

A test score alone missed these clear social strengths.

Amaral et al. (2017) saw the same pattern in Down syndrome: screening positive does not equal full ASD.

Vassos et al. (2023) later zoomed in on Angelman kids and found anxiety shows up as aggression when caregivers leave, adding detail to the social picture.

Waldron et al. (2023) tracked preschoolers with fragile X and non-syndromic ASD, showing face-looking drops more in ASD than in fragile X, matching Joanna’s point that social interest varies by syndrome.

If you run an ASD checklist on a child with Angelman, Cornelia de Lange, or Cri du Chat, pause before labeling. Watch the child play with you, with peers, and with parents across settings. Note laughing, hugging, or eager chatting—those real behaviors guide your next steps better than any cutoff score.