Non‐ketotic hyperglycinaemia presenting as pachygyria

Summary A 2‐day‐old infant with lethargy and hypoventilation had pachygyria and agenesis of the corpus callosum on CT scand. Increased concentrations of glycine in plasma and CSF, together with an increased CSF/plasma ratio, confirmed a clinical diagnosis of non‐ketotic hyperglycinaemia. This is the first report of pachygyria in this disorder, although agenesis of the corpus callosum is well recognized, and non‐specific gyral malformations have been described previously. The specific diagnosis of an inborn error of metabolism in infants with structural brain malformations is of critical importance for accurate genetic counselling.