The position of LRPPRC residue 354, at which the substitution A354V leads to LSFC with a clinically distinct cytochrome c oxidase deficiency and acute fatal acidotic crises, is in a buried area of α17, close to the mRNA-binding region (Fig. 1c and Extended Data Fig. 2a). This evidence concerns the gene LRPPRC and hyperinsulinemic hypoglycemia, familial, 4.