Catecholamine metabolite excretion in spina bifida.

The urinary excretion of vanilmandelic acid (VMA), homovanillic acid (HVA), and parahydroxyphenylacetic acid (pHPAA) was measured in 55 children with meningomyelocoele selected at random. In 96% of the children the levels of one or other of these compounds was significantly raised above the normal, usually by a factor of about 3. High VMA levels usually meant high HVA levels but the values for pHPAA appeared to be quite independent of the others. These results suggest a disorder of tyrosine metabolism, and the possible implications are discussed.