Keto Diet for NKH
Nonketotic hyperglycinemia is a rare inborn error of glycine metabolism due to deficient activity of the glycine cleavage system, a multi enzymatic complex consisting of four protein subunits: the P-protein, the H-protein, the T-protein, and the L-protein. The neonatal form of non-ketotic hyperglycinemia presents in the first days of life with encephalopathy, seizures, multifocal myoclonus, and characteristic “hiccups”. Rapid progression may lead to intractable seizures, coma, and respiratory failure requiring mechanical ventilation. A clinical trial with scavenges drugs decreasing glycine levels such as sodium benzoate, and with drugs reducing NMDA receptors excitatory properties, such as ketamine and dextromethorphan, have been tried but the outcome is usually poor; anti-epileptic therapy, moreover, is unable to control epileptic seizures. The ketogenic diet has been successfully tried for refractory epilepsy in pediatric patients. We report three cases affected by neonatal nonketotic hyperglycinemia and early myoclonic encephalopathy treated with the ketogenic diet. In our patient’s ketogenic diet, in association with standard pharmacological therapy, determined dramatic reduction of seizures and improved quality of life.