Hypersociability associated with developmental delay, macrocephaly and facial dysmorphism points to CHD3 mutations

Area of Science:

• Genetics and Developmental Biology
• Clinical Medicine

Background:

• CHD3-related syndrome (Snijders Blok-Campeau syndrome) is a rare genetic disorder caused by de novo pathogenic variants in the CHD3 gene.
• It is characterized by global developmental delay, intellectual disability, hypotonia, and behavioral issues, including autism spectrum disorder (ASD).

Observation:

• This report details a 21-year-old patient with a pathogenic de novo CHD3 variant, expanding the clinical description of the syndrome.
• A review of 35 previously reported patients and the current case highlights key features such as severe intellectual disability, dysmorphic facies, macrocephaly, and behavioral disorders.

Findings:

• The study identifies hypersociability, even in the presence of ASD, as a potentially suggestive feature of CHD3-related syndrome.
• This contrasts with typical presentations of syndromic intellectual disabilities, making hypersociability a notable observation.

Implications:

• The findings suggest that hypersociability, alongside developmental delay, macrocephaly, and dysmorphic facial features, could aid in diagnosing CHD3-related syndrome.
• Further research into the behavioral spectrum of this syndrome is warranted to refine diagnostic criteria and understand its unique characteristics.