The cause of DDOD syndrome (MIM: 220500) was first identified, from three unrelated cases, to be a de novo heterozygous variant (c.1516C>T; p.R506*) in the ATP6V1B2 gene (MIM: 606939) (Yuan et al., 2014). Here, ATP6V1B2 is linked to autosomal dominant deafness - onychodystrophy syndrome.