This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Glycine encephalopathy is an inherited metabolic disease characterized by abnormally high levels of an amino acid called glycine. Glycine is a chemical messenger that transmits signals in the brain. According to the symptoms the disease onset, glycine encephalopathy may be divided in:
Glycine encephalopathy is caused by changes (mutations) in the AMT, GLDC or GCSH genes which result in a deficiency of the enzyme that break-up the glycine. Diagnosis is based in the symptoms, the high glycine levels and the enzyme deficiency, as well as genetic testing. Inheritance is autosomal recessive. Treatment may include sodium benzoate to reduce the levels of glycine, N-methyl D-aspartate (NMDA) receptor site antagonists, anti-seizure drugs and ketogenic diet. About half of the babies with the classic form, die within a few weeks of life and the survivors may have motor delay, very small head, seizures and stiffness. In the transient form symptoms may improve with time.
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