Other Names for this Disease
- Glycine synthase deficiency
- Hyperglycinemia nonketotic
- Nonketotic hyperglycinemia
There have been affected individuals with "atypical" forms of the condition with variable signs and symptoms; these forms have ranged from milder disease with onset from late infancy to adulthood, to rapidly progressing and severe disease with late onset. The most common "atypical" form is known as the infantile form and is characterized by hypotonia, developmental delay and seizures. Individuals with this form may develop normally until signs and symptoms begin at approximately 6 months of age. As they age, many of these individuals develop intellectual disability, abnormal movements and behavioral problems. Other atypical forms of glycine encephalopathy can appear later in childhood or adulthood and cause a variety of medical problems that primarily affect the nervous system.
The Human Phenotype Ontology provides the following list of signs and symptoms for Glycine encephalopathy. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms.
The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature.
The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined.
Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
- Ada Hamosh, Gunter Scharer, Johan Van Hove. Glycine Encephalopathy. GeneReviews. November 24, 2009; http://www.ncbi.nlm.nih.gov/books/NBK1357/. Accessed 10/28/2011.
- Glycine encephalopathy. Genetics Home Reference. April 2007; http://ghr.nlm.nih.gov/condition/glycine-encephalopathy. Accessed 10/28/2011.