CASK and hereditary optic atrophy: Despite of the divergent phenotypic spectrum mutations in the CASK gene, it can present facial dysmorphism, sensorineural hearing loss, optic atrophy, retinopathy, hypohidrosis, microcephaly, developmental delay, limb hypertonia, pronounced cerebellar hypoplasia, various extent of pons hypoplasia, and a normal-sized corpus callosum [7, 35, 52].