IMMUNOLOGY

Detailed explanation-1: -Most myeloma cell lines are deficient in the enzyme hypoxanthine guanine phosphoribosyl transferase (HGPRT) although there are also others deficient in thymidine kinase (TK) and ouabain.

Detailed explanation-2: -The deficiency of the enzymatic activity of hypoxanthine-guanine phosphoribosyltransferase (EC 2.4. 2.8; HPRT) is associated with two OMIM items. Lesch-Nyhan syndrome (OMIM 300322) corresponds with virtually complete HPRT deficiency and was described by M. Lesch and W.

Detailed explanation-3: -The HGPRT deficiency causes a build-up of uric acid in all body fluids. The combination of increased synthesis and decreased utilization of purines leads to high levels of uric acid production. This results in both high levels of uric acid in the blood and urine, associated with severe gout and kidney problems.

Detailed explanation-4: -HGPRT is a transferase that catalyzes conversion of hypoxanthine to inosine monophosphate and guanine to guanosine monophosphate. This reaction transfers the 5-phosphoribosyl group from 5-phosphoribosyl 1-pyrophosphate (PRPP) to the purine.