[Hyperglycinemia without ketosis. Biochemical and enzymatic study].

We report a biochemical and enzymatic study of two neonatal cases of non ketotic hyperglycinemia. We report the comparative evolution of glycine level in plasma and CSF during a restrictive diet excluding glycine and serine. The high levels of glycine found in CSF and brain are likely to reflect the brain damage. After autopsy, the glycine synthase activity determination shows a significative partial deficiency in the liver and a total deficiency in the brain. Glycine synthase affinity for glycine is similar for controls and patients and this lead use to think that the deficiency is due to a diminished biosynthesis of the enzyme molecule.