Rare Skin Disease Caused By Defect In Genetic Code

Posted: October 06, 1987

Jack Trotter is a bright, curious 10-year-old who likes Cub scouts, T-ball and astronomy. He hopes to build his own robot and would like, someday, to become a professional actor.

But the slender, blond boy from Hockessin, Del., faces a serious handicap caused by a defect in his genetic code. Like 50,000 other Americans, he suffers from a rare disease, known as epidermolysis bullosa, or EB, that causes the outer layer of his skin to fall off.

If he turns a doorknob too hard, the skin on his palm will blister and peel. If he bumps into a classmate in a school hallway, the skin on his thigh will slough off. If he eats a potato chip the wrong way, the sensitive lining of his throat will rupture.

Much of the time, he walks around with dressings wrapped tightly around his legs to protect his fragile skin. When he takes off the bandages on his hands, the skin on his fingers and palms appears red and raw. Red bruises blemish his left arm.

When he was born, physicians told his parents that there was little hope Jack would live more than 2 1/2 years. But now, six operations and countless changes of dressings later, they are more optimistic about his future.

Earlier this month, scientists at Thomas Jefferson University launched a five-year effort to study the genetic causes of this rare disease. Armed with a $4.7 million grant from the National Institutes of Health, researchers hope to identify the precise gene that causes the defect and to develop new medical treatments.

Jouni Uitto, chairman of the dermatology department at Jefferson Medical

College, said that knowledge gained from this effort would also contribute information about other diseases, such as diabetes, atherosclerosis and lupus, which affect millions of people.

The work at Jefferson will be carried out at the university's Institute of Molecular Medicine, where research on the genetic causes of diseases is being conducted. There, more than 100 researchers are working to understand such genetically caused ailments as brittle-bone disease, sickle-cell anemia, cystic fibrosis, hemophilia and Duchenne muscular dystrophy.

The scientists are concentrating their EB research on a membrane that separates the outer skin layer, or epidermis, from the lower layer, or dermis. For reasons that are not fully understood, these layers are not properly connected in EB victims, causing the outer layer to slough off.

As part of the research, Robert Knowlton, an assistant professor at Jefferson, is leading the effort to determine the precise location and structure of the gene that causes EB. And Jefferson scientists are seeking to develop both a diagnostic probe that would tell prospective parents if their child would be born with EB and new treatments for this disease.

Both Jack's mother, Mary, and father, Robert, a chemical engineer at the Du Pont Co., did not know until Jack was born that they each carried a recessive gene for EB. The couple's other son, Michael, 8, does not have the disease.

The Trotter family is doing all it can to aid Jack. He is given a variety of medications to protect him from infection and inflammation. He takes piano lessons to strengthen his fingers.

"We are grateful for every day of Jack's life," Mary Trotter said during a recent interview. "When he was born, there was little hope. Now, we believe that there is."