Disruption of PHF21A causes syndromic intellectual disability with craniofacial anomalies, epilepsy, hypotonia, and neurobehavioral problems including autism.
Hyung-Goo Kim, Jill A Rosenfeld, Daryl A Scott and 25 others
PMID 31649809WHAT IT FOUND
Seven patients with PHF21A gene variants all had intellectual disability and language delay.
Four also had epilepsy, three had autism, and three had obesity. This links the gene to a syndrome involving craniofacial anomalies, hypotonia, and neurobehavioral problems.
Key findings
01All seven patients in the study presented with developmental delay, intellectual disability, language delay, and impaired motor skills.
02Seizures were observed in four of the seven patients, while autism spectrum disorder was present in three patients.
03The study identified six unique variants in the PHF21A gene across the seven patients, with four being frameshift variants, two nonsense variants, and one missense variant.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs
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What it does not show
The study is a case series of only seven patients, which limits the generalizability of the phenotype. The authors could not demonstrate that the truncated variants without the intrinsically disordered region (IDR) are expressed because blood samples were unavailable, precluding definite conclusions about the role of this region. Functional characterization of the specific mutations, particularly the missense variant, requires further study to confirm the mechanism. The study does not provide longitudinal data on how the phenotype evolves over time beyond the ages reported.
Declared interests
The study was funded by the Korean Ministry of Trade, Industry and Energy, the National Research Foundation of Korea, and the Qatar Biomedical Research Institute. The authors declared no conflicts of interest.
The easy way to misread this
Do not assume that all patients with PHF21A variants will present with the full spectrum of features. For example, not all patients had epilepsy, autism, or hypotonia, and the severity of intellectual disability varied. This is a small case series, so the frequency of specific symptoms may not reflect the broader population of individuals with this genetic condition.