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Some immune deficiencies linked to enzyme abnormality
What is perhaps the "first clear-cut enzyme abnormality in immune deficiency" has been found now in five children with combined immunodeficiency disease.All five—in this continent and Europe—lack adenosine deaminase (also known as ADA) in their erythrocytes and in their lymphocytes. Their parents (and also some relatives) have lower than normal levels of adenosine deaminase, leading investigators to the conclusion that they are heterozygous carriers.Adenosine deaminase is important in purine metabolism because it is an aminohydrolase that converts adenosine to inosine. Its prime importance is in what are termed the "salvage" pathways of nucleic acid metabolism—pathways in which pre-formed purines and pyrimidines enter the cells and are interconverted to the proper precursors and energy sources in preparation for synthesis of DNA and RNA. These pathways have been established for red cells, at least, and a few studies indicate the same is true
Medical News. JAMA. 1973;224(5):571-582. doi:10.1001/jama.1973.03220180003002