Hyperglycinemia: A Defect in Glycine Cleavage Reaction

Abstract

A girl with hyperglycinemia of nonketotic type was presented. The liver biopsied from the patient was studied for glycine metabolism. It was found that the yield of 14C02 from glycine-l-14C and the rate of 11C incorporation into serine from glycine-1 -14 IC as well as glycine-2 14C were extremely low in the patient's liver than in control livers, while the patient's liver showed normal activities of serine-hydroxymethylase and serine-dehydratase.hese findings indicate that the primary lesion of hyperglycinemia of nonketotic type is a defect in the glycine cleavage reaction which gives rise to the formation of CO2, methylene-tetrahydrofolate and ammonia from glycine.

Coexistence of Defective Activity in Glycine-Cleavage Reaction and Propionly-CoA Carboxylase in the Liver of a Hyperglycinemic Child

“…On the other hand, in cases of hyperglycinemia a defective activity of glycine cleavage enzyme of the liver was demonstrated by Tada et al (1969), then confirmed by de Groot et al (1970).…”

“…): S.M., a female, was first admitted into the University Hospital at the age of 1 year, when a diagnosis of hyperglycinemia was established and a defective activity of glycine cleavage enzyme was demonstrated in the liver obtained by surgical biopsy frcm this patient (Tada et al 1969). At that time methylmalonic aciduria was not detected by chromatography of urine specimens.…”

Valproic Acid Exacerbated Infantile Spasms and Induced Novel Complex Partial Seizures in an Infant with Non-ketotic Hyperglycinemia

“…The seizure pattern begins with frequent myoclonic jerks and then changes to infantile spasms and generalized tonic seizures. The electroencephalogram (EEG) findings of affected patients are characterized by a suppression-burst pattern, which subsequently changes to a pattern of high-voltage slow waves [1,2]. Despite early and appropriate treatment with sodium benzoate and/or dextromethorphan, the neurological outcomes of affected neonates remain poor [3].…”

A one-base deletion (183delC) and a missense mutation (D276H) in the T-protein gene from a Japanese family with nonketotic hyperglycinemia

“…The fundamental defect lies in the mitochondrial glycine cleavage system (GCS) (Tada et al 1969). The GCS consists of four individual constituents, referred to as P-, H-, T-, and L-protein.…”