Nonketotic hyperglysynemia in newborns

Abstract

Non-ketotic hyperglycinemia or glycine encephalopathy is a rare genetic metabolic disease with an autosomal recessive mode of inheritance, characterized by a deficiency in the activity of the glycine cleavage enzyme and, as a consequence, the accumulation of large amounts of glycine in all tissues and body fluids, including the brain.Neonatal forms begin to appear in the first hours and days of life in the form of progressive lethargy, hypotension and myoclonic seizures, leading to apnea and, often, death. Surviving children have profound mental retardation and hard-to-control seizures. Simultaneous study of glycine in blood plasma and cerebrospinal fluid, as well as molecular genetic testing of biallelic genes through gene sequencing are the basic diagnostics of non-ketotic hyperglycemia.However, there is currently no effective treatment for severe glycine encephalopathy, and the main goal of treatment is to reduce the concentration of glycine with sodium benzoate in plasma by blocking glycinergic receptors at the level of the N-methyl-D-aspartate receptor.