GAINESVILLE---University of Florida researchers have identified the gene that causes a rare, fatal childhood disease, according to a report published in Today's issue (7/18) of the journal Nature.
While only 10 to 20 Americans have Chediak-Higashi syndrome, the gene's discovery could have far-reaching implications for tens of thousands of patients who suffer from cancer or autoimmune disorders such as lupus.
Children born with the syndrome have an inherited immune deficiency that weakens their ability to battle bacteria and viruses. They typically die by age 6 of infection or cancer, usually lymphoma or leukemia.
The gene normally acts as a master switch to regulate the transport of proteins within cells, said Dr. Stephen Kingsmore, a molecular geneticist at the Center for Mammalian Genetics at UF's College of Medicine. In Chediak-Higashi syndrome, the gene functions abnormally and many proteins fail to be delivered to their correct destinations within cells.
Scientists also believe this gene plays a role in regulating the spread and development of cancers in general, and in protecting against certain autoimmune disorders.
"This is significant for several reasons. Nobody knew what caused this fatal disease," Kingsmore said. "Now we can design a diagnostic test. And hopefully by understanding the gene we can forge better treatments for Chediak-Higashi syndrome, and in the long run offer genetic therapy for it."
People and mice who have Chediak-Higashi syndrome are much more susceptible to cancer, which spreads faster and more widely than in typical cancer patients, Kingsmore added.
A better understanding of the gene's role in the spread of cancer could lead to new medications or treatments for all cancer patients, he said.
Meanwhile, researchers discovered that mice with Chediak-Higashi syndrome are protected against some forms of autoimmune disease, especially the complications many lupus patients develop.
"This discovery has the potential to be a treatment for lupus as it relates to kidney problems," said Dr. Doyt Conn, the national Arthritis Foundation's senior vice president for medical affairs. "Hopefully in the near future a medication may be available."
Researchers identified the gene by first mapping its location in mice with Chediak-Higashi syndrome, sifting through piece after piece of DNA to determine which gene was mutated. They then isolated it in people with the disease.
The two-year effort was funded by the National Institutes of Health, the Arthritis Foundation and the American Cancer Society.
The study was conducted in conjunction with researchers at the University of Texas Southwestern in Dallas, Vanderbilt University and Glaxo-Wellcome, a pharmaceutical company.
"The next step is to characterize the gene to find out how it does
what it does," Kingsmore said. "So far we have a piece of the puzzle. We now
need to figure out precisely how it causes the disease, how it protects
against kidney disease in lupus, and how it makes people susceptible to cancer."