Your browser does not support javascript:   Search for gard hereSearch for news-and-events here.


Genetic and Rare Diseases Information Center (GARD)

Print friendly version

Glycine encephalopathy

Other Names for this Disease
  • Glycine synthase deficiency
  • Hyperglycinemia nonketotic
  • Nonketotic hyperglycinemia
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.


Glycine encephalopathy is an inherited condition characterized by abnormally high levels of an amino acid called glycine. Glycine acts as a chemical messenger that transmits signals in the brain. Glycine encephalopathy is caused by the shortage of an enzyme that normally breaks down glycine in the body, thus allowing excess glycine to build up in tissues and organs, particularly the brain. Symptoms typically appear during infancy or early childhood and include a lack of energy (lethargy), feeding difficulties, weak muscle tone (hypotonia), abnormal jerking movements, breathing problems, seizures, and intellectual disability. It is caused by mutations in the AMT, GLDC or GCSH genes and is inherited in an autosomal recessive manner.[1][2]
Last updated: 11/10/2011


  1. Glycine encephalopathy. Genetics Home Reference. April 2007; Accessed 10/28/2011.
  2. Hamosh A, Scharer G, Van Hove J. Glycine encephalopathy. GeneReviews. November 2009. ; Accessed 11/10/2011.
Your Questions Answered
by the Genetic and Rare Diseases Information Center

3 question(s) from the public on Glycine encephalopathy have been answered. See questions and answers. You can also submit a new question.

Basic Information

  • Genetics Home Reference (GHR) contains information on Glycine encephalopathy. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) is a federation of more than 130 nonprofit voluntary health organizations serving people with rare disorders. Click on the link to view information on this topic.

In Depth Information

  • The Online Mendelian Inheritance in Man (OMIM) is an catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs.  Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Glycine encephalopathy. Click on the link to view a sample search on this topic.

Insurance Issues