Autism in Angelman syndrome: an exploration of comorbidity.

Trillingsgaard et al. (2004) watched 16 children with Angelman syndrome. They gave each child the ADOS-G, a gold-standard autism test. The team wanted to see how many would hit the autism cutoff.

They also checked each child's mental age. The goal was to learn if Angelman behaviors look like autism or just slow development.

Thirteen of the 16 kids scored above the ADOS-G autism line. That is 81 percent, a very high rate.

Yet the authors say the scores may lie. Low mental age alone can create 'false positives.' The kids waved, flapped, and avoided eye contact, but the writers call this delay, not true autism.

Walz (2007) asked 248 parents the same question and got the same warning. Autistic-like signs are common in Angelman, but the pattern differs from idiopathic ASD. The big survey extends the target's caution to a wider age span.

Mertz et al. (2014) tracked the same deletion subtype for 12 years. Autistic features stayed flat while receptive language slowly rose. The follow-up supports the delay view; it supersedes the old idea of a fading autism trajectory.

Thompson et al. (2003) seems to disagree. Their single teen with paternal-uniparental-disomy Angelman showed almost no autistic signs. The clash is real but genetic: deletion cases (target) look more autistic than paternal-UPD cases (John).

Before you write 'autism' in an Angelman file, check mental age and genotype. A high ADOS score may reflect global delay, not social deficit. Pair the test with real-world probes: does the child seek adults for tickles or laughter? If yes, teach play and joint attention first, and reserve autism labels for teams that see clear social avoidance.