Team diagnoses Mila the orangutan with rare genetic disease

Mila is a six-year-old orangutan born at the Indianapolis Zoo. (Credit: Fred Cate/Indianapolis Zoo)

Researchers have diagnosed a Sumatran orangutan with a rare genetic disease.

It’s the first time the disease has been confirmed molecularly in a primate other than a human.

The six-year-old orangutan, named Mila, was born at the Indianapolis Zoo in 2016. Mila had a history of dark urine that turned brown upon standing since birth, but has never shown other symptoms. Researchers from the Indiana University School of Medicine medical and molecular genetics department collected and analyzed DNA, diagnosing Mila with the disease, called alkaptonuria.

The study is published in Molecular Genetics and Metabolism.

“This was an unexpected finding that ended years of questions about this animal,” says Marcus Miller, assistant professor of clinical medical and molecular genetics and principal investigator of the study. “We’re proud of this collaborative effort with the zoo that will hopefully lead to better care and treatment of Mila moving forward.”

Alkaptonuria is a rare, autosomal recessive disorder, a genetic disease caused by deficiency of an enzyme called homogentisate 1,2-dioxygenase. As an infant, the only symptom is urine that turns black upon standing. Symptoms typically progress slowly, but can lead to chronic joint pain and decreased mobility later in life.

There have been several reports of the disease in non-human primates, but never any long-term studies, so it is unclear how the disease will affect Mila over time. However, having this diagnosis means that veterinarians don’t have to worry about other potential issues.

“I think the best part about these results is we can de-escalate some of the other studies that might have been recommended,” says Theodore Wilson, assistant professor of clinical medical and molecular genetics.

“We don’t need to use anesthesia for imaging, obtain a kidney biopsy or have guests or veterinarians worried. Even though her urine does still turn dark after being out in the environment, fortunately, now it doesn’t need to be a problem that is alarming.”

“People with this disease typically don’t develop symptoms until much later in life, usually in their 30s or 40s,” says Melissa Fayette, associate veterinarian for the Indianapolis Zoo. “We will continue to monitor Mila closely and perform regular preventive health exams to detect any secondary pathologies that may arise.”

Source: Indiana University