Glycine encephalopathy is a disorder that disrupts glycine metabolism, leading to glycine accumulation in various body tissues, including the brain.
Glycine buildup can result in a range of severe symptoms such as lethargy, seizures, breathing difficulties, and even coma, often leading to fatal outcomes. Surviving patients commonly experience intellectual disability and ongoing seizures. While most cases manifest during the neonatal period with rapidly progressing symptoms, there are also infantile, childhood, and adult-onset forms of the condition, each presenting with different medical issues primarily affecting the nervous system. There is no treatment for this condition and management of symptoms is supportive.
Glycine encephalopathy is caused by pathogenic (disease-causing) variants in either the AMT or GLDC genes; both exhibit autosomal recessive inheritance. This means that both parents must be carriers in the same gene (AMT or GLDC) to have a 25% chance to have a child with the condition.
Other names for this condition are non-ketotic hyperglycinemia.
Resources:
Genetic and Rare Diseases Information Center
Revised July 2023
