Exome sequencing has limits, UF researcher finds

A University of Florida researcher has found that one type of genetic test may not be able to identify a particular type of muscular dystrophy, leaving patients with this disease at risk of going undiagnosed if they only receive this kind of testing. UF Genetics Institute member Peter B. Kang, M.D., examined the efficacy of exome sequencing in identifying pathogenic mutations for limb-girdle muscular dystrophy, or LGMD. It was the largest study of its kind focusing on patients in the U.S. with this disease, which causes muscle weakness, particularly in the shoulders and hips. The researchers identified mutations in multiple genes associated with muscle disease. Less than half, or 40 percent, were diagnosed using exome sequencing. “Exome sequencing is a powerful technology, but it’s not the be-all and end-all of genetic diagnosis,” Kang said.  — Ellison Langford

Stem cells used in patient with chemotherapy-induced heart failure

For the first time, UF Health cardiologists have implanted stem cells into the heart of a breast cancer survivor with heart failure. The researchers will be studying whether stem cells from healthy subjects can improve heart function in patients who have been treated with a group of chemotherapy drugs called anthracyclines. In about 3 to 5 percent of patients, the drugs cause a form of heart failure called anthracycline-induced cardiomyopathy, according to Carl Pepine, M.D., a professor of medicine in the UF College of Medicine, who is leading the research at UF. The researchers are hoping that injecting mesenchymal stromal cells — cells formed in bone marrow that have not yet developed for a specific role in the body — into the hearts of patients with this kind of cardiomyopathy can instigate the regeneration or repair of damaged and scarred tissue.   — Morgan Sherburne

Timing is critical in causing genital defects

UF researchers have identified cells targeted by a male hormone and found that an excess of that hormone at a specific time can cause genital defects in female mice. Scientists have long known that prenatal exposure to androgens, such as the hormone testosterone, causes genital defects in females. Androgens act as masculinizing hormones, directing formation of male genitalia and preventing formation of a vaginal opening in boys. When a female embryo produces excessive amounts of androgen, it disrupts the development of the urethral and vaginal openings. Instead of developing as separate tubes with individual openings, they are born with only one opening. Using mouse models, Christine Larkins, Ph.D., a research assistant professor in the department of molecular genetics and microbiology at the UF College of Medicine, working with Ana Enriquez, an undergraduate, and Martin Cohn, Ph.D., a professor in the department of molecular genetics and microbiology, showed the timing and duration of androgen exposure influence the severity of vaginal malformations.  — Ellison Langford