Final answer:
Gout is a type of arthritis caused by an accumulation of uric acid crystals in the joints, due to either overproduction or under excretion of uric acid. A gene defect in the enzyme xanthine oxidase, targeted by allopurinol, can contribute to this excess. Other factors include diet and conditions like Von-Gierke's disease.
Step-by-step explanation:
Gout is a form of arthritis characterized by an excess of uric acid in the blood, leading to the formation of uric acid crystals in the joints. This condition may result from the body's overproduction of uric acid due to cell death and nucleic acid breakdown, or from inadequate excretion by the kidneys.
The specific gene defect most commonly associated with excess uric acid leading to gout is in the function of the enzyme xanthine oxidase. This enzyme's activity can be reduced by the drug allopurinol, which helps prevent the formation of uric acid and thereby mitigates the symptoms of gout. Additionally, conditions like Von-Gierke's disease, characterized by an overproduction of PRPP leading to excess uric acid, can predispose an individual to gout. Lifestyle factors, such as a diet high in certain foods like fructose and purine-rich foods, can also contribute to elevated uric acid levels.