SLC25A15 and ornithine translocase deficiency: However, direct sequencing of the SLC25A15 gene identified two novel heterozygous mutations in exon 5 of the SLC25A15 gene (ENST00000338625.9): c.649G>A (p.Gly217Arg) and c.706A>G (p.Arg236Gly) (Figure 1A), different from the 50 already reported SLC25A15 gene mutations (5, 8–10), strongly suggesting a case of HHH syndrome.