After ruling out mutations and deletions/rearrangement of the mtDNA, molecular analysis of nuclear genes involved in mitochondrial diseases by NGS revealed that the patient was a compound heterozygote for two variations in the SERAC1 gene: a nonsense substitution previously described as disease‐causing (Tort et al., 2013) and a novel splice site variant resulting in exon 3 skipping. This evidence concerns the gene SERAC1 and inborn mitochondrial metabolism disorder.