SPTBN4 and developmental and epileptic encephalopathy: Mendelian disease-gene links are increasingly being recognized for the spectrin genes, with SPTAN1, SPTBN1, SPTBN2 and SPTBN4 linked to neurological diseases such as developmental and epileptic encephalopathy (DEE), ataxia, hereditary spastic paraplegia, and hereditary motor neuropathy.