The interstitial duplication 15q11.2-q13 syndrome includes autism, mild facial anomalies and a characteristic EEG signature.
Maternal 15q11.2-q13 duplication always brings autism and a tell-tale EEG pattern.
01Research in Context
What this study did
Doctors looked at the children who all carried an extra copy of chromosome 15.
Every extra piece came from the mother.
Each child also had autism.
The team ran EEGs and checked faces for small differences.
What they found
All kids with the maternal 15q duplication had autism.
Bigger or smaller duplications did not change how severe the autism was.
The EEG showed a clear spike-and-wave pattern in every child.
Faces had mild traits like a wide mouth or flat nasal bridge.
How this fits with other research
Cramm et al. (2009) mapped a different duplication on chromosome 8 in one autistic teen.
Both studies link extra DNA to autism, but the 15q region is now a stronger marker because it showed up in every case.
van Rijn et al. (2008) tied Klinefelter syndrome (47,XXY) to autism traits.
That paper looked at behavior, while Nora et al. added a brain-wave signature, so the two studies fill different pieces of the same puzzle.
Mulder et al. (2020) sharpened autism tools for fragile X.
Nora et al. give you a new genetic clue to watch for, while A et al. show how to tune the surveys you already use.
Why it matters
If you see a client with autism plus wide mouth or flat nose, ask the doctor about chromosome 15 testing.
An EEG spike-and-wave pattern can back up the gene test.
Knowing the 15q duplication helps you explain why skills may stall and why seizures are more likely.
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02At a glance
03Original abstract
Chromosomal copy number variants (CNV) are the most common genetic lesion found in autism. Many autism-associated CNVs are duplications of chromosome 15q. Although most cases of interstitial (int) dup(15) that present clinically are de novo and maternally derived or inherited, both pathogenic and unaffected paternal duplications of 15q have been identified. We performed a phenotype/genotype analysis of individuals with interstitial 15q duplications to broaden our understanding of the 15q syndrome and investigate the contribution of 15q duplication to increased autism risk. All subjects were recruited solely on the basis of interstitial duplication 15q11.2-q13 status. Comparative array genome hybridization was used to determine the duplication size and boundaries while the methylation status of the maternally methylated small nuclear ribonucleoprotein polypeptide N gene was used to determine the parent of origin of the duplication. We determined the duplication size and parental origin for 14 int dup(15) subjects: 10 maternal and 4 paternal cases. The majority of int dup(15) cases recruited were maternal in origin, most likely due to our finding that maternal duplication was coincident with autism spectrum disorder. The size of the duplication did not correlate with the severity of the phenotype as established by Autism Diagnostic Observation Scale calibrated severity score. We identified phenotypes not comprehensively described before in this cohort including mild facial dysmorphism, sleep problems and an unusual electroencephalogram variant. Our results are consistent with the hypothesis that the maternally expressed ubiquitin protein ligase E3A gene is primarily responsible for the autism phenotype in int dup(15) since all maternal cases tested presented on the autism spectrum.
Autism research : official journal of the International Society for Autism Research, 2013 · doi:10.1002/aur.1284