Sheffield, a pediatric researcher with University of Iowa Children's Hospital, a part of University of Iowa Hospitals and Clinics, is one of about 320 scientists nationwide to hold a prestigious Howard Hughes Medical Institute appointment. His laboratory specializes in identifying disease genes based on their location on human chromosomes. Specifi cally, he is identifying genes involved in hereditary blindness, deafness, autism, and heart disease.

"From my perspective, almost every disease has a genetic component. It is a challenge to identify a gene or genes that may be only one component of a common disease," he says. To make the research more manageable, Sheffield initially focused on genetic diseases that seem to be caused by a single, mutated gene.

"We believe these can give us clues to the more complex genetic disorders like hypertension, obesity, glaucoma, and diabetes that affect so many people's lives," says Sheffi eld, who holds a bachelor's degree in zoology from Brigham Young University, a master's degree in developmental biology from BYU, and a doctorate in developmental biology and a medical degree from the University of Chicago.

Sheffield, who came to University of Iowa Children's Hospital in 1990, is part of a research team that recently discovered the gene which, if mutated, causes the most common form of glaucoma--an eye disease affecting up to five million Americans. His lab also has made dramatic inroads into single gene diseases like Pendred's syndrome (early-onset hearing loss in newborns) and Bardet-Biedl syndrome (BBS features include blindness, obesity, mental retardation, diabetes, and extra fingers and toes).

Sheffield, who directs the Division of Medical Genetics in the Department of Pediatrics, says identifying specific genes that cause diseases will allow people to be tested and put into potentially effective treatment or risk categories.

"Eventually we want to be able to determine what disease you're at the greatest risk of getting," he says. "But people like absolutes. They want to know if they have a zero percent or 100 percent chance. The reality is that medicine is never an absolute. What we want to do is identify those who are at greatest risk for a specifi c disease so that they can be treated early and effectively."

Genetic researcher Val Sheffield, M.D., Ph.D., uses his expertise to expand our knowledge of the human genome and molecular genetics.