SPG11 and deafness: For example, the causal gene for juvenile amyotrophic lateral sclerosis and Kjellin syndrome SPG11, GABRA4 causing autism, DMXL2 linked to an autosomal dominant form of deafness and early infantile epileptic encephalopathy, as well as NTNG2 associated with a neurodevelopmental disorder are all involved in synapse function and synaptic transmission [176–186].