humans lack the enzyme uricase which is involved in elimination of excess nucleic acid purines & nitrogenous waste products through production and excretion of allantoic acid;
hence in humans, uric acid is end product of purines degradation;
gouty arthritis begins w/ deposition of MSU crystals in synovial & periarticular tissue;
factors related to microtophus formation:
reduced solubility of MSU at the periphery of the body because of lower temperatures;
weight bearing (MTP joint incurs high force / area)
