Pyridoxine and infantile myoclonic seizures

Abstract

The urinary excretion of acetylkynure-nine, 3-hydroxykynurenine, 3-hydroxyanthranilic acid, xanthurenic acid, kynurenine, and kynurenic acid have been investigated in 15 children with infantile myoclonic seizures. One child was found to have true pyridoxine dependency without a demonstrable defect in the metabolism of tryptophan to nicotinic acid. A significant impairment of kynureninase activity was detected in 5 patients. TUs defect could be resolved by 0. 1 mg. /kilogram of pyridoxine intravenously. One additional patient with abnormal kynureninase function required 1 mg. /kilogram of pyridoxine for correction. The pyridoxine-depen-dent child showed a dramatic clinical response to pyridoxine, and in 4 of the others there was tentative evidence of clinical improvement with vitamin Bg administration. Response to treatment could not be predicted by the laboratory studies. Conjectures regarding the nature of the defects involved are described.