Threonine dehydratase deficiency: a probable cause of non-ketotic hyperglycinaemia.

A patient with classical symptoms of non-ketotic hyperglycinaemia (NKH) is presented. Threonine dehydratase was undetectable in a liver autopsy specimen, which was obtained within 1 h of death and immediately frozen at -70 degrees C. Activities of four marker enzymes were normal. This represents the first documentation of an inborn error of threonine metabolism and a new explanation of NKH.