A mentally retarded young woman with severe behaviour problems was found to excrete large amounts of glutathione due to a generalized gamma-glutamyl transpeptidase deficiency. As in the only other case described in detail, plasma levels and renal reabsorption of the amino acids were normal. In the parents' urine, plasma and leukocytes, enzyme activity was normal but in their cultured fibroblasts it was below the minimum for the control range. An autosomal recessive mode of inheritance is suggested. The implications of these findings for possible role of the gamma-glutamyl cycle in amino acid transport are briefly discussed.
We present our findings in two unrelated patients with the characteristic clinical and radiological features of the Winchester syndrome. The histological findings in gum and skin biopsies taken from one of the subjects, indicated excessive collagen turnover (active phagocytosis, an active endoplasmic reticulum, and an abundance of fibrillogranular material of probable collagen origin). An abnormal oligosaccharide was detected in urine from both patients which was identified as a trisaccharide containing one fucose and two galactose residues. The finding of this oligosaccharide may prove a useful marker in other cases of this rare syndrome and may help elucidate the underlying biochemical defect.
SUMMARY In this study a perfusion technique has been used to investigate in vivo jejunal absorption and transmural potential difference evoked by the neutral amino acids phenylalanine (56 or 20 mmol/l) and glycine (20 mmol/l), the dibasic amino acid lysine (56 or 5 mmol/l), and a dipeptide glycyl-l-phenylalanine (20 mmol/l) in 11 children with pancreatic insufficiency due to cystic fibrosis and in three children with other causes of exocrine pancreatic insufficiency. Net absorption and potential difference evoked by phenylalanine in both cystic fibrosis and pancreatic insufficiency, and net absorption of glycine in cystic fibrosis were significantly reduced; but the absorption of lysine and glycyl-l-phenylalanine was normal. Absorption of the constituent amino acids from the dipeptide was normal or increased in cystic fibrosis. Thus, these studies show a defect in active absorption of neutral amino acids in cystic fibrosis with pancreatic insufficiency and exocrine pancreatic insufficiency. We speculate that pancreatic factors participate in neutral amino acid absorption.
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