However, Gustafson et al. have recently described and suggested that the variant p.(Glu27Lys) in SSBP1 gene can interfere with mtDNA replication and precipitate the introduction of large scale mtDNA deletions with clinical manifestations across the clinical spectrum of Pearson, Kearns-Sayre and Leigh syndromes [27]. This evidence concerns the gene SSBP1 and Leigh syndrome.