Cystine crystals are flat colorless plates and have a characteristic hexagonal shape with
equal or unequal sides. They often aggregate in layers. Their formation is favored in acidic
urine.
Cystine crystalluria or urolithiasis is an indication of cystinuria, which is an inborn error of metabolism involving defective renal tubular reabsorption of certain amino acids including cystine. Sex-linked inheritance is suspected since male dogs are almost exclusively affected. Many breeds, as well as mongrels, have been reported affected . Renal function otherwise appears to be normal and, aside from a tendency to form uroliths, the defect is without serious consequence. |
Last Updated: January 16, 1996