Abstracts

Rationale: Glycine encephalopathy, previously referred to as non-ketotic hyperglycinemia, is an autosomal recessive inborn error of metabolism involving the glycine cleavage system, with an incidence of 1:60,000. As a result of this defect, glycine accumulates in body tissues including the brain. Those with the severe form suffer from lethargy, coma, seizures, apnea, and early death. Glycine encephalopathy is diagnosed by a ratio of = 0.08 CSF glycine: Plasma glycine. In this report, we will show the use of Ketogenic Diet as a therapy to treat intractable seizures caused by glycine encephalopathy.  Methods: An 11-year-old male was transferred to our institution for evaluation and management of glycine encephalopathy.  The patient was born full term via vaginal delivery by healthy Puerto Rican non-consanguineous parents with a birth weight of 3.9 kg.  He was diagnosed with glycine encephalopathy after he was admitted as a neonate in a comatose state.The patient was started on the ketogenic diet as an inpatient in the pediatric EMU on a 2:1 ratio and titrated by 0.5 ratio daily to a goal of 3:1. During this admission the patient was maintained on his medication regimen as prior to admission:  Dextromethorphan, Lamotrigine, Clobazam, Levetiracetam, and Phenobarbital. The patient was discharged home after a 5-day hospitalization. While the patient remained at baseline, non-responsive to commands, with generalized spasticity and contractures, upon discharge, the patient showed a dramatic increase in alertness and wakefulness compared to the day of admission.  Results: Plasma glycine levels decreased following diet initiation and an improvement in both the amino acid profile and seizure frequency were documented (Figure 1 and Table 1, respectively). No seizures were seen after the first day presenting with ketones (day 2 of diet initiation) for the first 5 months of diet therapy and since then, the patient has had a greater than 80% seizure reduction. Conclusions: The case presented suggests that a ketogenic diet along with standard treatments for glycine encephalopathy should be considered to treat intractable epilepsy.  Larger studies are needed to evaluate the diets effect on plasma glycine levels. Funding: Not applicable