| Abstract: | Alkaptonuria has been diagnosed in a laboratory born, five year old, female orangutan. In man, this relatively rare amino acid metabolic disorder is characterized by arthritis, pigmentation of cartilage, and darkening of the urine upon standing. The color change is due to oxidation of homogentisic acid not normally found in the urine. The condition in man is a simple Mendelian recessive trait characterized by the absence of homogentisic acid oxidase activity. At two years of age, the affected orangutan was noted to void urine of normal color, which upon standing turned a very dark maroon color. Clinically the animal appeared normal; and the results of a urinalysis, hemogram, and survey radiographs confirmed this evaluation. Nonspecific laboratory determinations used to diagnose alkaptonuria in man were positive. Homogentisic acid in the urine was confirmed by paper chromatography, and a quantitative evaluation was made by a commercial laboratory. The orangutan has shown no clinical change or evidence of ochronosis during the past three years, and quarterly survey radiographs show no evidence of osteoarthropathy. The affected orangutan has half brothers and sisters in the colony but no full sibling. Both parents are young, however, and are being paired in an attempt to produce siblings. It is hoped that additional animals with this metabolic defect will become available for use as potential models for studying this inborn error of metabolism. |
