Treatment for Rare Genetic Disease Shows Promise: Enzyme Replacement Works in Mice
ST. LOUIS -- When Shunji Tomatsu, M.D., Ph.D., associate professor of pediatrics at Saint Louis University, began a presentation this summer at an international symposium about Morquio A Syndrome, he didn’t realize that researchers, patients and their families in the audience wore T-shirts imprinted with his photo and the caption “Our Hero.”
“I was astonished,” says Tomatsu, who also is a research pediatrician at SSM Cardinal Glennon Children’s Medical Center.
Tomatsu is one of a handful of scientists worldwide working to find a treatment for Morquio A Syndrome, a rare and deadly degenerative genetic disease, which is known in scientific circles as mucopolysaccharidosis IVA. He told those assembled for the Mucopolysaccharidosis (MPS) Symposium in Venice, Italy, about a promising therapy he has researched, which works in an animal model to treat the disease.
“If we treat a newborn mouse with a synthetic version of the enzyme they are missing, their condition becomes completely normal. If we treat an adult mouse, it’s partially improved. Early diagnosis and early treatment is most effective,” Tomatsu says.
“It worked very well and that’s why the Swiss pharmaceutical company, Inotech, has joined us in developing a drug therapy. We have hope to do a clinical trial in the human population.”
Research Holds Promise
That’s good news to the 1,200 patients in developed countries that have Morquio Syndrome. “It’s a rare disease -– found in one in 200,000 births,” says Tomatsu, who has studied the illness for more than 20 years.
“It’s a devastating and systemic bone disease and there currently is no real treatment.”
Patients who have Morquio Syndrome are missing a certain enzyme –- glycosaminoglycans –- which causes the accumulation of a unique substance in the body.
This substance causes a series of severe bone problems that begin at about age 1. They include delayed and stunted growth; a neck bone so fragile it can break after a fall; a floppy wrist that is small and appears double-jointed; knocked knees; an overly prominent breastbone; a compressed spinal cord; and destroyed hip joint that prevents teens from walking.
“In later life, they might have a serious heart valve disease and infectious disease to the lung. The only treatment for these patients is orthopedic surgery and if care is good, patients can expect to live between 30 and 40 years. If left untreated, the life expectancy of those with Morquio Syndrome is their 20s or 30s.”
Focus on a Rare Disease
Tomatsu is a leading researcher who is studying Morquio Syndrome with scientists from the United Kingdom, Germany, Japan and Switzerland. He began studying the disease 21 years ago in Japan, and came to Saint Louis University in 1995 to develop a drug therapy to fight Morquio Syndrome. He is a chief medical officer for the International Morquio Organization.
Tomatsu says his group has just established a registry to track the progression of the disease in 320 patients from more than 30 countries.
This is an important step in showing the natural history of the disease, he says.
Next year, he hopes to invite around 50 patients who have Morquio Syndrome to Saint Louis University and SSM Cardinal Glennon Children’s Medical Center for more extensive tests so researchers might more fully understand the clinical progression of the illness.
“Our goal is to become a center to treat these patients. We want to stop the disease. That’s our hope,” Tomatsu says. “The good news is there’s a timetable. We hope to get a clinical trial by the end of next year.”
Established in 1836, Saint Louis University School of Medicine has the distinction of awarding the first M.D. degree west of the Mississippi River. Saint Louis University School of Medicine is a pioneer in geriatric medicine, organ transplantation, chronic disease prevention, cardiovascular disease, neurosciences and vaccine research, among others. The School of Medicine trains physicians and biomedical scientists, conducts medical research, and provides health services on a local, national and international level.