Among CSS subtypes, CSS9 (OMIM#615866) is caused by heterozygous mutations in the SRY-related HMG-box 11 (SOX11) gene, which is located on chromosome 2p25.2 and is important in chromatin remodeling related to SWI/SNF complex functions (6). This evidence concerns the gene SOX11 and intellectual developmental disorder with microcephaly and with or without ocular malformations or hypogonadotropic hypogonadism.