Mitochondrial DNA or Genomic DNA Variant(s): Utility of Exhaustive Sequencing in Leigh Syndrome

Pathogenic variants in the nuclear gene NDUFAF8 are a rare cause of mitochondrial complex I deficiency with only three cases described to date. We report here a new case of NDUFAF8 deficiency confirming the phenotype of NDUFAF8-induced complex I biochemical defect, Leigh syndrome and premature death. As a mitochondrial DNA variant in a gene encoding a complex I subunit was also identified in this patient, we discuss the molecular heterogeneity of Leigh syndrome and the need to explore the mitochondrial and nuclear genome to ensure a reliable diagnosis.