If a person has alkaptonuria how might their urine smell?

Individuals with alkaptonuria often have urine that has a distinct, unusual odor due to the accumulation of homogentisic acid, which is excreted in the urine. This can give the urine a brownish color and a smell reminiscent of old, rancid or musty odors. The odor may become more pronounced when the urine is exposed to air, as the homogentisic acid oxidizes.