P 518. Vitamin B6-Dependent West’s Syndrome: An Unexplained Case

Background: After describing vitamin B6-dependent epilepsies for the first time more than 50 years ago, the different genetic backgrounds of these diseases have been increasingly revealed in recent years. However, despite the extensive knowledge about the different causes of the diseases, not all vitamin B6-dependent epilepsies can be definitively clarified.

Methods/Results: We report the case of a 7-month-old infant treated with idiopathic West’s syndrome characterized by BNS seizures and hypsarrhythmia. Interventions with prednisolone, vigabatrin and sulthiame had no effect, whereas vitamin B6 showed rapid and stable therapeutic success.

Diseases that lead to pyridoxine-dependent epilepsy may be caused by disruption in vitamin B6 metabolism (PNPO, ALPL, or PLPBP mutations) or by defects in other metabolic pathways with secondary pyridoxal phosphate activation (ALDHA7A1 and ALDH4A1 mutations). In the case described here, however, no disease-causing mutation could be detected in any of the genes mentioned.

Conclusion: In addition to the specific effects described, pyridoxine also has a so-called nonspecific antiepileptic effect, which is partly due to its role as a cofactor in the conversion of excitatory glutamate into inhibitory GABA.

It remains unclear whether pyridoxine could exert an unspecific effect, which is significantly superior to all other drugs used, or whether another previously unknown defect in the vitamin B6 metabolism is the cause of its positive effect.