Abnormal tryptopham metabolism in congenital erythroid hypoplastic (Diamond-Blackfan) anaemia

Tryptophan loading was performed in a child with Diamond-Blackfan anaemia as well as in his parents and two control persons. There was a fivefold increase of anthranilic acid and kynurenine excretion beside a marked generalized aminoaciduria in the proband; in the parents and the controls no such phenomenon could be demonstrated. The importance of the finding is discussed and investigation of tryptophan metabolism before the first blood transfusion is recommended. The finding cannot be used as a heterozygote test.