eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-01-30 4 1 55 58 5524 article Salman Alrokayan 1 Department of Biochemistry, College of Science, King Saud University, Riyadh, (Kingdom of Saudi Arabia) Deficiencies of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) have been implicated in the pathogenesis of severe combined immunodeficiency disease (SCID). This study examined the activities of ADA and PNP enzymes in 450 school children and 20 suspected SCID patients. The results showed a significant increase in serum ADA of SCID patients as compared to controls whereas the activity of PNP did not differ significantly between the two groups. Single stranded conformational polymorphism (SSCP) analysis did not reveal any molecular defect in ADA and PNP genes of patients’ suggesting that the suspected patients were not suffering from immunodeficiency due to ADA or PNP deficiency. Further studies on large number of SCID patients are needed to determine the involvement of allelic variants or novel mutations resulting ADA/PNP deficient immunodeficiency in Saudi population. https://www.biotech-asia.org/vol4no1/role-of-adenosine-deaminase-and-purine-nucleoside-phosphorylase-in-severe-combined-immunodeficiency-disease-a-biochemical-and-molecular-study/ Adenosine deaminase; Purine nucleoside; Immunodeficiency disease; Biochemical; molecular study