Gene discovery may aid Marfan's diagnosis.
At present, physicians can detect Marfan's syndrome only in people with the most extreme form of the disease. Such patients are unusually tall and loose-jointed, have long, spider-like fingers, and may suffer from dislocated eye lenses. Less striking forms of Marfan's may go undiagnosed until the major blood vessel leading from the victim's heart bursts during strenuous physical activity, causing sudden death.
As early as the 1950s, physicians surmised that Marfan's was a genetic disease involving connective tissue because it affects bones, tendons and the cartilage that shores up major blood vessels. Last year, a group led by the late David W. Hollister at the University of Nebraska Medical Center in Omaha attributed Marfan's to a defect in fibrillin, the protein that provides the structural scaffolding between cells (SN: 8/4/90, p.79.)
In the July 25 NATURE, U.S., Japanese and French members of Hollister's original team report that they have linked Marfan's syndrome to a fibrillin gene on chromosome 15. The researchers, led by Francesco Ramirez of the Mount Sinai School of Medicine in New York City, also report finding a gene on chromosome 5 that codes for a different version of fibrillin, which may cause a related disorder of the fingers called congenital contractural arachnodactyly.
In the same issue of NATURE, two other papers further characterize chromosome 15's fibrillin gene. At Shriners Hospital for Crippled Children in Portland, Ore., Lynn Y. Sakai and her co-workers deciphered 70 percent of the DNA sequences that make up the gene. Sakai, now at Duke University in Durham, N.C., and another group led by Harry C. Dietz at Johns Hopkins University in Baltimore, also describe mutations in the fibrillin genes of two people who developed Marfan's spontaneously without inheriting defective genes.
These discoveries "should permit the design of definitive diagnostic tests [for Marfan's]," writes Johns Hopkins geneticist Victor A. McKusick in an accompanying editorial. He says the findings should also aid a project analyzing Lincoln's remains to determine whether the President suffered from the disease (SN: 5/25/91, p.335).
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|Date:||Jul 27, 1991|
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