Mutations in the TBC1D24 gene (MIM 613577) cause familial infantile myoclonic epilepsy (FIME; 605021) and early infantile epileptic encephalopathy-16 (EIEE16; 615338), both inherited with an autosomal recessive trait.
TBC1D24 loss of function has been associated to idiopathic infantile myoclonic epilepsy, as well as to drug-resistant early-onset epilepsy with intellectual disability.
Recessive TBC1D24 gene mutations have been described in two families: an Italian family afflicted with familial infantile myoclonic epilepsy, and an Arab family with focal epilepsy and intellectual disability syndrome.
The disorder is allelic with familial infantile myoclonic epilepsy, where intellect and neurologic examination are normal, highlighting the phenotypic variation with mutations of TBC1D24.
TBC1D24 overexpression resulted in a significant increase in neurite length and arborization and the FIME mutations significantly reverted this phenotype.