Mosaicism for Cohen-Gibson Syndrome in a Female Individual With Overgrowth and Neurodevelopmental Delay.
Fei Song, Manuel Michels, Beate Betz et al.
✦ AI-curated · Sources linked
Case in brief
A 12-year-old girl presented with tall stature, dysmorphic features, developmental delay, and congenital anomalies. Genetic evaluation revealed a likely pathogenic mosaic variant in the EED gene, with varying allele fractions across different tissues. This case underscores the importance of multi-tissue analysis for accurate diagnosis and genetic counseling in overgrowth syndromes.
What made this case unusual
The case highlights postzygotic mosaicism for a pathogenic EED variant, which is atypical as most reported cases involve heterozygous germline variants.
Diagnostic / clinical pearl
Clinicians should consider the possibility of mosaicism in patients with overgrowth and neurodevelopmental delay, as it can complicate diagnosis and management.
Why it matters
This case emphasizes the need for deep sequencing and multi-tissue analysis in genetic evaluations to improve diagnostic accuracy in complex syndromes.