Hidden Clues
Introduction
Ophthalmologists don’t usually recommend a urine test to diagnose eye diseases. But urine can provide clues to genetic mutations that cause retinitis pigmentosa, a hereditary eye disease that impairs vision and results in blindness. Patients suffering from the disease carry two copies of a mutation of the gene that produces the enzyme dehydrodolichol diphosphate synthase and synthesises organic compounds called dolichols in the body. Dolichols can be easily detectedfrom urine.
Source
Down to Earth, November 2013