PSAT1 and hyperinsulinemic hypoglycemia, familial, 4: Phosphoserine aminotransferase (PSAT) uses the amino‐group of glutamate for serine synthesis.53 PSAT deficiency has been reported in patients with Neu‐Laxova syndrome 2, characterised by central nervous system anomalies, facial dysmorphic features, anomalies of limb and genitalia, intrauterine growth retardation, skin disorders, and other congenital abnormalities.54 An overlapping phenotype caused by PSAT mutations is described in one family under the name phosphoserine aminotransferase deficiency.55 It is questionable whether this concerns the same syndrome.