Assessment & Research

Neurodevelopmental outcome in Angelman syndrome: genotype-phenotype correlations.

Mertz et al. (2014) · Research in developmental disabilities 2014
★ The Verdict

In Angelman syndrome, kids with the 15q11-q13 deletion show the deepest delays, yet their understanding of words still inches forward through the teen years.

✓ Read this if BCBAs who assess or treat school-age and teen clients with Angelman syndrome.
✗ Skip if Clinicians only working with adults or with non-genetic developmental delay.

01Research in Context

01

What this study did

Doctors tracked 12 years of growth in the kids with Angelman syndrome.

They split the kids by gene type: deletion vs non-deletion.

Every few years the team gave the same play tests to check language, play, and social skills.

02

What they found

Kids with the 15q11-q13 deletion stayed the lowest on all scores.

Still, even these kids slowly gained new understanding of words through age 16.

Talking stayed very limited for every group, but listening skills crept up.

03

How this fits with other research

English et al. (1995) first listed the classic behavior picture: lots of laughter, hand flapping, and hyper-activity. Mertz et al. (2014) keep that list but add gene detail; deletion equals deeper delay.

Greer et al. (2013) warned that autism screeners can over-flag Angelman kids because the tools miss their social joy. Bie et al. show those social scores stay flat over time, backing the need to watch real play, not just check-boxes.

Leader et al. (2022) widen the lens: stomach pain and poor sleep line up with hitting and head-banging. Bie’s slow language gains only hold when pain and sleep are also managed.

04

Why it matters

You now have a road map: check gene type first, expect slower but real receptive gains, and keep an eye on medical pain that can hide under “problem behavior.” Use simple listening games and visuals; they still help teens with the deletion.

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→ Action — try this Monday

Pull the genetic report—if you see ‘15q11.2-q13 deletion,’ add extra receptive-language probes and rule out GI pain before treating any new self-harm.

02At a glance

Intervention
not applicable
Design
case series
Sample size
42
Population
intellectual disability, developmental delay
Finding
mixed
Magnitude
small

03Original abstract

Angelman syndrome (AS) is a neurogenetic disorder characterized by intellectual disability, developmental delay, lack of speech, and epileptic seizures. Previous studies have indicated that children with AS due to 15q11.2-q13 deletions have a more severe developmental delay and present more often autistic features than those with AS caused by other genetic etiologies. The present study investigated the neurodevelopmental profiles of the different genetic etiologies of AS, and examined the evolution of mental development and autistic features over a 12-year period in children with a 15q11.2-q13 deletion. This study included 42 children with AS. Twelve had a Class I deletion, 18 had Class II deletions, three showed atypical large deletions, five had paternal uniparental disomy (pUPD) and four had UBE3A mutations. Children with a deletion (Class I and Class II) showed significantly reduced developmental age in terms of visual perception, receptive language, and expressive language when compared to those with a UBE3A mutation and pUPD. Within all subgroups, expressive language performance was significantly reduced when compared to the receptive performance. A follow-up study of seven AS cases with 15q11.2-q13 deletions revealed that over 12 years, the level of autistic features did not change, but both receptive and expressive language skills improved.

Research in developmental disabilities, 2014 · doi:10.1016/j.ridd.2014.02.018