Clinical and Genetic Analysis of SMARCC2‐Related Diseases in Three Chinese Patients

Coffin‐Siris syndrome (CSS) is a rare, clinically and genetically heterogeneous disorder characterized by coarse facial features, microcephaly, intellectual disability (ID), developmental delay (DD), and hypo/aplastic digital nails and phalanges, typically of the 5th digit. CSS is an autosomal dominant disease resulting from mutations in genes encoding components of BRG1/BRM‐associated factor (BAF) chromatin remodeling complexes. More than 300 CSS patients have been reported with variants in genes in the BAF pathway. Recently, patients carrying SMARCC2 variants have been reported to be associated with CSS8. However, as the number of cases increases, many patients do not exhibit the representative clinical symptoms of CSS. Additional case reports and clinical studies will contribute to a redefinition of SMARCC2‐related disorders.