The etiology of alkaptonuria is a genetic mutation that affects the HGD gene, which provides instructions for producing an enzyme called homogentisate 1,2-dioxygenase. This enzyme is involved in the breakdown of an amino acid called phenylalanine.
In individuals with alkaptonuria, a specific mutation in the HGD gene leads to a deficiency or complete absence of the homogentisate 1,2-dioxygenase enzyme. As a result, phenylalanine is not properly broken down and accumulates in the body. The excess phenylalanine is then converted into a compound called homogentisic acid, which is excreted in the urine and gives it a dark color when exposed to air. This discoloration is a characteristic symptom of alkaptonuria.
Alkaptonuria follows an autosomal recessive pattern of inheritance, which means that an affected individual inherits two copies of the mutated gene (one from each parent). Individuals who carry only one copy of the mutated gene are typically unaffected carriers.
It’s worth noting that alkaptonuria is a rare genetic disorder, and its symptoms primarily involve the musculoskeletal and urinary systems. If you suspect you or someone you know may have alkaptonuria or have questions about this condition, it is important to consult with a healthcare professional for an accurate diagnosis and appropriate management.
