Tumor gene found for disorder
By Sid Perkins
UPI Science News
WASHINGTON, Aug. 7 (UPI) -- Scientists say they have identified the second
of two genes known to cause tumors associated with tuberous sclerosis
complex (TSC), a relatively common developmental disorder.
The international team of researchers, led by Dr. David Kwiatkowski of
Brigham and Women's Hospital in Boston, reports the discovery today in the
journal Science.
TSC has a wide variety of symptoms, including seizures, benign tumors, and
variable emotional and cognitive disabilities such as autism. TSC affects
about one person in every 6,000.
Kwiatkowski says researchers located the gene, called TSC1, on chromosome
9. The gene makes a protein called hamartin, named after hamartomas, a
type of tumor common to TSC. These tumors are made up of multiple cell
types and are found in the brain, kidneys, eyes and other organs. Brain
scans typically reveal cortical tubers, the firm potato-like nodules that
give the disorder its name.
Scientists first linked TSC to chromosome 9 in 1987, but the specific
mutations in the TSC1 gene are only now being identified. TSC2, a second
gene associated with the disorder, was located on chromosome 16 in 1992
and identified in 1993. Both of these genes are thought to be tumor
suppressors, and they join more than a dozen other genes known to play an
important role in cell growth.
Kwiatkowski says any person with TSC has a 50 percent chance of passing
along the defective gene to his or her children, who will then have the
disorder. About 65 percent of the cases, however, occur as "sporadic
mutations" in people with no family history of TSC.
---[
Copyright 1997 by United Press International.
All rights reserved.
---[