TIMM50 and hyperinsulinemic hypoglycemia, familial, 4: Patients presenting with pathogenic mutations in TIMM50 are rare, but common symptoms include severe intellectual disabilities, epileptic spasms, microcephaly, moderate elevation of plasma lactate levels, variable mitochondrial Complex V deficiency and 3-MGA-uria (MGCA9, MIM #617698) [55–57].