[Still another cause of hypermethioninemia in children: S-adenosylmethionine synthetase deficiency].

One case of hypermethioninaemia discovered on systematic neonatal screening examination is reported. This metabolic disorder was associated with growth retardation, anorexia, digestive disturbances, and a strong smell of "boiled cabbage" in urine and sweat. With a 6-year follow up, psychomotor and growth developments were excellent under a low methionine containing diet, in spite of a persistent pathological hypermethioninaemia. A deficiency in S-adenosyl-methionine synthetase and an abnormal kinetics of this enzyme were found in a liver tissue sample obtained by biopsy. Otherwise, the excretion of alpha-keto-gamma-methyl-thiobutyric acid was increased with, however, no abnormality in the metabolism of folates. Finally, the probability of an autosomal recessive transmission is discussed.