Alkapus, often referred to in the context of alkaptonuria, is a rare genetic disorder caused by the deficiency of the enzyme homogentisate oxidase, leading to the accumulation of homogentisic acid in the body. This condition results in darkening of urine upon exposure to air, as well as potential joint and tissue damage due to the deposition of pigment. Patients may experience Arthritis and other complications over time. Management focuses on symptom relief and monitoring for associated conditions.