SSBP1 and optic atrophy: This paradigm has been changed by the identification of mostly dominant, but also recessive, mutations affecting the SSBP1 protein, encoding the mitochondrial single-stranded DNA-binding protein that is essential for mtDNA replication, associated with optic atrophy (OPA13), retinal dystrophy with foveopathy, but also with deafness, myopathy and a remarkable nephropathy leading to kidney failure requiring transplantation [117,118,119].