Abnormal Tryptophan Metabolism in Patients with Adult Celiac Disease, with Evidence for Deficiency of Vitamin B6*

Increased urinary excretion of certain aromatic metabolites of tryptophan has been described in a wide variety of pathologic conditions: pyridox- ine deficiency either primary or secondary to isoniazid or deoxypyridoxine (1); metabolic dis- eases such as in phenylketonuria (2), porphyria (3, 4), and Hartnup's disease (5); a variety of malignancies-metastatic malignant carcinoid (6), bladder carcinoma (4, 7), leukemia (8), and lymphoma (8); mental disorders (4); pregnancy (9, 10) ; and collagen vascular diseases (4, 11).