The inclusion of a third filtering step based on HPO terms, or including all genes from the MitoCarta database [20] in the narrowing down of genetic-variants discovered by WES, corroborated the presence of the above change but also identified NM_018480.7: c.83T > C (p.Val28Ala) in homozygous fashion in TMEM126B, which encodes a transmembrane component of the mitochondrial complex I. Biallelic changes in TMEM126B has been related to the mitochondrial complex I deficiency, nuclear type 29 (MIM#618250). The gene discussed is TMEM126B; the disease is hyperinsulinemic hypoglycemia, familial, 4.