Glycine encephalopathy
Overview
Glycine encephalopathy (medical condition): A rare disorder of amino acid metabolism where glycine and proline are unable to be metabolized properly due to defects in the glycine cleavage system. See also Non-ketotic hyperglycinemia: »Introduction: Non-ketotic hyper
Symptoms
Some of the symptoms of Glycine encephalopathy incude: * Listlessness * Spasticity * Seizures * Involuntary muscle contractions * Opisthotonos
Diagnosis
Diagnosis/testing. Glycine encephalopathy is suspected in individuals with elevated glycine concentration in urine. An increased CSF-to-plasma glycine ratio suggests the diagnosis. Reliable enzymatic confirmation of the diagnosis requires measurement of glycine cleavage enzyme (GCS) activity of liver obtained by biopsy or autopsy. The vast majority of affected individuals have no detectable activity; such testing is available on a research basis only. Molecular genetic testing of the GLDC gene, encoding the P-protein component of the GCS complex and accounting for disease in 80% of individuals with NKH, and the AMT gene, encoding the T-protein component of the GCS complex and accounting for disease in 10-15% of individuals with NKH, is available on a clinical basis. Molecular genetic testing of the GCSH gene (encoding the H-protein component of the GCS complex) is available on a clinical basis.