Glycine Encephalopathy (AMT-Related) (AMT)
Glycine encephalopathy (AMT-related) is a pan-ethnic autosomal recessive disease caused by pathogenic variants in the gene AMT. Symptoms may begin soon after birth or later in infancy. Babies who are symptomatic soon after birth experience lethargy, muscle weakness, and muscle jerks. These early symptoms resolve but patients have intellectual disability and seizures throughout life. Individuals whose symptoms start later in infancy experience muscle weakness, seizures, and developmental delay. Long-term symptoms include severe to mild intellectual disability and seizures. Rarely, an individual affected with a milder form of the disease can present later in life with less severe symptoms. Life expectancy is variable, depending on the severity of symptoms, and can range from infancy to adulthood. It is not currently possible to predict the severity of disease based on the inherited variants.
For information about carrier frequency and residual risk, please see the residual risk table.