PDSS1 and Leber hereditary optic neuropathy: These include two siblings with infantile-onset neurosensorial deafness and optic atrophy, resulting from a mutation ([c.924T>G] [p. Asp308Glu]) in the PDSS1 gene [24]; one child with a more severe birth-onset phenotype with kidney failure and death at 16 months, resulting from PDSS1 mutations ([c.661C>T] [p. Arg221Ter] and [c661-662inST] [pArg221Leufs16]) [25]; and two sisters (aged 6 and 14 years) with sensorineural deafness and optic atrophy, resulting from a PDSS1 mutation ([c.735G>T] [p. Gln245His]) [26].