PPOX and progressive external ophthalmoplegia: They are the genes encoding MutS, E. coli homolog associated with deficiency of Endometrial carcinoma; DNA Polγ involved in deficiency of progressive external ophthalmoplegia and male infertility; protoporphyrinogen oxidase associated with deficiency of porphyria variegate; ATPase family gene 3-like 2 associated with deficiency of hereditary spastic paraplegia; and three mitochondrial ribosomal proteins, L3, S12 and S14, which are linked to moebius syndrome 2, and deafness, autosomal dominant nosyndromic sensorineural 4 and 7, respectively (Table 6) [38]–[41]