Alkaptonuria, its symptoms and causes you should know

This is a very rare hereditary disease for which the patient’s urine turns black. It belongs to a group of diseases that are classified as inborn errors of metabolism due to hereditary causes.

Causes of alkaptonuria

Genetic defect

A defect in the HGD gene causes alkaptonuria. This gene abnormality causes the body to be unable to properly break down certain amino acids, particularly tyrosine and phenylalanine. Therefore, homogentisic acid accumulates in the skin and is excreted from the body through urine, which turns brown-black when exposed to air.

Alkaptonuria is hereditary. If both parents carry a copy of the defective gene, each of their children has a 25% (1 in 4) chance of developing the disease.

Symptoms of alkaptonuria

black urine

Black urine is the main symptom of the disease, but sometimes others occur, such as arthritis or the appearance of dark spots in the eyes.

Diagnosis of alkaptonuria

urine test

A urine test can tell if a person has alkaptonuria by mixing the urine with ferric chloride.

Treatment and drug management of alkaptonuria

Vitamin C

In many cases, taking vitamin C allows the patient to achieve rapid improvement.

Prevention of alkaptonuria

Find out if there is a family history

When considering having children, it is advisable to carry out genetic testing to find out whether there is a risk of transmitting the disease.