Coffin–Siris Syndrome in a Patient with Hirschsprung's Disease—Expanding the Phenotype by Mutation ARID1B: A Case Report and Literature Review

Abstract Coffin–Siris syndrome (CSS) is a rare syndrome with autosomal dominant inheritance, and it is characterized by intellectual disability, hypotonia, aplasia/hypoplasia of the distal phalanx of fifth fingernail, feeding difficulties, growth restriction, short stature, speech delay, hirsutism/hypertrichosis, and thinning hair on the scalp. Hearing impairment has also been described in some patients. In this article, we describe the case of a male patient diagnosed with CSS who, at 15 days of life, underwent surgery for megacolon correction and a later intestinal biopsy revealed the affected segment compatible with Hirschsprung's disease (HSCR). This patient was found to have a variant in ARID1B (p. [Pro934Glnfs*5]) in a component of the BAF complex which plays an important role in regulating the expression and differentiation. In addition, it mediates responses to environmental signals resulting from an ATP-dependent chromatin remodeling complex. This case added a unique clinical characteristics and a rare genetic variant in the repertoire of CSS.