What is Alkaptonuria

Alkaptonuria is a rare genetic disorder that affects the body's ability to break down certain amino acids, specifically phenylalanine and tyrosine. This condition is caused by a mutation in the HGD gene, which leads to a deficiency of the enzyme homogentisate 1,2-dioxygenase.

Individuals with alkaptonuria experience a buildup of homogentisic acid in their body, which can cause a range of symptoms. One of the most notable signs is the darkening of urine upon exposure to air, turning it black. This discoloration is due to the oxidation of homogentisic acid.

Alkaptonuria can also lead to the accumulation of homogentisic acid in connective tissues, leading to a condition called ochronosis. Ochronosis can cause joint and cartilage problems, leading to arthritis-like symptoms and stiffness. Additionally, it can affect other tissues such as the heart and kidneys.

Diagnosis of alkaptonuria is typically done through urine tests to detect the presence of homogentisic acid. While there is no cure for this condition, management focuses on symptom relief and preventing complications. Treatment options may include dietary modifications, pain management, and regular monitoring of organ function.

Alkaptonuria is an autosomal recessive disorder, meaning both parents must carry the mutated gene for a child to inherit the condition. Genetic counseling is recommended for individuals with a family history of alkaptonuria or those planning to have children.