,21,22 MtSSB (SSBP1, encoded by SSBP1) is an indispensable component of the mtDNA replication machinery and, as demonstrated previously, defects in SSBP1 may lead to an isolated or syndromic phenotype characterized by optic atrophy and retinal dystrophy.1 Here, SSBP1 is linked to inherited retinal dystrophy.