THE introduction of mass screening programs for the detection of inborn errors of metabolism1 almost inevitably reveals a variety of new artefacts which those who deal with these diseases must learn to recognize. We describe here one of these artefacts: D-methioninuria due to ingestion of Dl-methionine-fortified infant formula.
Report of a Case
The patient, the second-born of male dizygotic twins delivered in a hospital in a nearby community at 32 weeks' gestation, weighed 1,814 gm (4 lb) at birth. His brother weighed 1,561 gm (3 lb 7 ounces). The mother, a primipara, was convalescing from viral hepatitis complicated by myocarditis when spontaneous labor began. The infant spent the first three days in an incubator."Very foul stools" were noted at 4 days of age, and this was more or less persistent throughout his nursery course. After initial 5% dextrose feedings, the infant was given a cow's milk formula, and