CHD3-related Snijders Blok-Campeau syndrome with Spastic Paraplegia, Ataxia, and Situs Inversus.

The Chromodomain Helicase DNA-binding (CHD) protein family is ATP-dependent chromatin remodeling proteins that utilize energy produced by ATP hydrolysis to regulate chromatin structure and thereby modulate gene expression. The earliest report of a CHD3 gene mutation was by O'Roak, who found it during whole exome sequencing of 189 autism families in 2012. In 2018, Snijders Blok systematically assessed the autosomal dominant neurodevelopmental disorder caused by CHD3 gene damage, known as Snijders Blok-Campeau syndrome (SNIBCPS, OMIM 618205). Its typical features include global developmental delay, speech delay, mild to severe intellectual disability, hypotonia, autism, and distinctive facial features such as macrocephaly (microcephaly in minority), prominent forehead and so on. This article reports a patient of slow speech, intellectual disability, epilepsy, spastic paraplegia, ataxia and situs inversus with a CHD3 gene mutation. The features of spastic paraplegia, ataxia, and situs inversus have not been reported previously. In conclusion, CHD3 gene mutations represent a rare disease with diverse clinical phenotypic features. This patient contributes valuable insights into the understanding of CHD3 gene mutation manifestations, expanding the scope beyond previously reported features.