To date, CASK-related disorders comprise various developmental disorders such as MICPCH [4,5], X-linked intellectual disability [7,11], FG syndrome [12,13], pediatric epilepsy syndrome [5,6,7,8,9,10], ophthalmologic phenotypes [13,14] (such as nystagmus), hearing impairment [5,7,11], and autism spectrum disorders [15]. The gene discussed is CASK; the disease is Nystagmus.