[Disorders of amino acid metabolism in a patient with identified thiamine deficiency].

Report on a serious disturbance of amino-acid metabolism in a 56 year old male patient suffering from thiamine-(vitamin B-1) deficiency, as proven by clinical history and examination and by laboratory data. In comparison with a group of 75 normal male persons also evaluated by the same laboratory this patient--while thiamine deficient--had markedly elevated serum concentrations outside the physiologic range of glutamic acid, glutamine, proline, citrulline, ornithine, histidine, lysine, phenylalanine, tyrosine and leucine, whereas his serum concentrations of taurine, serine and isoleucine were comparably definitely lowered. Following six to seven days of daily i.m. injections of 200 mg of thiamine each, this imbalance of amino-acid homeostasis disappeared except for that of taurine and--questionably--that of phenylalanine. In view of the absence of other exogenous or endogenous potential causes for this, it must be presumed that the thiamine-pyrophosphate deficiency caused the imbalance of amino-acid metabolism by consecutively disturbing the function of the alpha-ketoglutarate-, pyruvate- and p-hydroxy-phenylpyruvate- decarboxylase chains respectively. Possible connections between thiamine-deficiency and lowered serum concentrations of serine, taurine and isoleucine are being discussed.