Biallelic variants in Protein Only RNase P Catalytic Subunit (PRORP) have recently been associated with a newly defined syndrome, combined oxidative phosphorylation deficiency 54 (COXPD54) (MIM #619737), encompassing a phenotypic spectrum of Perrault syndrome and leukodystrophy [1]. The gene discussed is PRORP; the disease is Perrault syndrome.