THERAPEUTIC EFFICACY OF MAGNESIUM VALPROATE IN SUCCINIC SEMIALDEHYDE DEHYDROGENASE DEFICIENCY

Succinic semialdehyde dehydrogenase deficiency (SSADHD or gammahydroxybutyric aciduria), a disorder of γ-aminobutyric acid (GABA) metabolism, manifests as a slowly progressive or static encephalopathy. The latter encompasses prominent cognitive dysfunction, neuropsychiatric morbidity and epilepsy.We report safe and effective treatment with MgVPA in an adolescent female with SSADHD and seizures refractory to a broad spectrum of antiepileptics. MgVPA therapy (20 mg/Kg/day) was introduced at 7 years based upon behavioural difficulties and EEG alterations without adverse effects. Therapy was halted at age 13 years, and reintroduced at 14 years, due to new onset complex partial seizures. EEG demonstrated improvement in epileptiform activity, associated with behavioural improvement in disinhibition, aggression and coprolalia. Though typically avoided in SSADHD due to inhibitory effects on any residual enzymatic activity, valproate was effective and safe in our patient. Sodium valproate has previously demonstrated therapeutic utility in SSADHD, but the use of the magnesium conjugate has not been reported. Epilepsy remains well controlled in our patient, with concomitant improvements in behavioural symptoms . Our results suggest that MgVPA intervention may have utility in selected cases of SSADHD