Laboratory abnormalities included decreased total protein and albumin levels, elevated hepatic transaminase levels, and evidence of associated iron and zinc deficiency. Of the 5 patients with a low serum zinc level, patients 1, 5, and 8 improved without zinc supplementation, but patients 6 and 10 did receive zinc supplementation. Patient 2 had increased IgA, IgM, and IgG levels, but these results were not believed to be contributory to the cause of the patient's condition, as the tests were drawn to rule out an immunodeficiency. Patient 6 had a positive radioallergosorbent test result to milk, soy, and barley. Patient 10 had an increased stool α1-antitrypsin level, suggesting a malabsorptive state, but had a negative sweat chloride test result for cystic fibrosis. Other laboratory investigations that had negative or normal results were as follows: DNA analysis for mutations for cystic fibrosis (patient 12); tests for sweat chloride (patients 2, 3, 5, 10, and 11), stool α1-antitrypsin (patients 5 and 6), thyroid function (patients 1, 2, 5, and 6), serum amino acids (patients 5, 11, and 12), urine organic acids (patients 1, 5, 11, and 12), biotinidase (patients 1 and 12), immunoglobulins (patients 6, 7, and 9), human immunodeficiency virus antibody (patient 11), rapid plasma reagin (patient 11), D-xylose (patient 9), and T-lymphocyte subsets (patient 7); and mitogen studies (patient 2). Skin biopsy specimens were obtained in 7 of the 12 patients and revealed findings consistent with kwashiorkor with either confluent parakeratosis with pallor of the outer third of the epidermis or confluent parakeratosis and psoriasiform hyperplasia.