Histidinuria

Histidinuria is a metabolic disorder characterized by the excessive excretion of histidine in the urine. Histidine is an essential amino acid that plays a role in protein synthesis and is a precursor to other important molecules. In individuals with histidinuria, the kidneys are unable to reabsorb histidine efficiently, leading to its increased presence in urine. This condition is generally considered benign and often discovered incidentally during routine urinalysis.

The underlying cause of histidinuria is typically an inherited defect in the renal tubular transport system responsible for reabsorbing histidine. While there are different genetic forms, the most common is an autosomal recessive pattern, meaning an individual must inherit two copies of the altered gene to be affected. In most cases, histidinuria does not cause any noticeable symptoms or health problems. The body's production and utilization of histidine are usually not significantly impacted, as the excess excreted is due to impaired kidney function rather than a deficiency in histidine itself.

Diagnosis is made by measuring histidine levels in the urine. Treatment is generally not required, as the condition is asymptomatic. Management focuses on ensuring adequate hydration and monitoring for any potential, though rare, associated complications. Genetic counseling may be offered to affected individuals and their families.