CASK

More than 35 CASK gene mutations have been identified in people with CASK-related intellectual disability. This disorder affects brain development and has two main forms: a severe form called microcephaly with pontine and cerebellar hypoplasia (MICPCH), and a milder form called X-linked intellectual disability (XL-ID) with or without nystagmus.

The mutations that cause CASK-related intellectual disability affect the role of the CASK protein in brain development and function. MICPCH is caused by mutations that eliminate CASK function, while mutations that impair the function of this protein cause XL-ID with or without nystagmus. Nystagmus refers to rapid, involuntary back-and-forth eye movements. Affected individuals with nystagmus may have CASK gene mutations that disrupt the interaction between the CASK protein and the protein produced from the FRMD7 gene, leading to problems with the development of the oculomotor neural network and resulting in abnormal eye movements.

MedlinePlus Genetics provides information about FG syndrome