Pyridoxine-dependent seizures in Dutch patients: diagnosis by elevated urinary alpha-aminoadipic semialdehyde levels

BACKGROUND: Pyridoxine-dependent seizures (PDS) is a rare, autosomal recessively inherited disorder. Recently alpha-aminoadipic semialdehyde (alpha-AASA) dehydrogenase deficiency was identified as a major cause of PDS, which causes accumulation of both alpha-AASA and pipecolic acid (PA) in body fluids. METHODS: We studied urinary and plasma alpha-AASA and PA levels in 12 Dutch clinically diagnosed patients with PDS. RESULTS: Alpha-AASA was elevated in both urine and plasma in 10 patients. In these patients plasma PA levels were also elevated but urinary PA levels were normal. DISCUSSION: In all patients with clinically definite PDS, and in most patients with probable or possible PDS, the clinical diagnosis of PDS could be confirmed at the metabolite level. Non-invasive urinary screening for alpha-AASA accumulation provides a reliable tool to diagnose PDS and can save these patients from the classical and potentially dangerous pyridoxine withdrawal test to prove PDS.