Expression of TBC1D24 appears ubiquitous, with the exception of spleen, and is predominant in the developing brain, in chondrocytes from the distal phalanges, and in the scull [2, 3], thus explaining why TBC1D24 mutations can induce epilepsies, mental retardation, onychodystrophies and osteodystrophies, as reported in the DOORS syndrome (OMIM #220500), or infantile myoclonic epilepsies (OMIM #605021) and epileptic encephalopathies (OMIM #615338). The gene discussed is TBC1D24; the disease is deafness-onychodystrophy syndrome.