As a consequence, defects in these V0a isoforms lead to different hereditary disorders: mutations in V0a1 cause epilepsy (MIM 619970) [7, 8], loss of V0a3 leads to autosomal recessive osteopetrosis (MIM 259700), V0a4 is associated with renal tubular acidosis and hearing loss (MIM 602722), and mutations in the gene ATP6V0A2 encoding subunit V0a2 cause autosomal recessive cutis laxa type 2A (ARCL2A, MIM 219200), also called wrinkly skin syndrome (WSS). This evidence concerns the gene ATP6V0A2 and wrinkly skin syndrome.