Scott
Heyman loves his job in the produce section of a Publix supermarket
near his familys Marietta home. He rides the bus to work
and back and is preparing to someday live on his own.
Now
twenty-three, Scott (at left with sister, Carly) was diagnosed
with fragile X syndromethe most frequently inherited cause
of mental impairmentwhen he was nine. His parents sought
help in understanding why their middle child was hyperactive,
made strange noises, and had difficulty communicating.
We
really noticed the delayed speech by age four. Scott was in
speech therapy, but his progress was minimal. His pediatrician
wasnt very helpful, he just kept saying Einstein didnt
talk until he was five, says Scotts mother, Gail
Heyman, now the director of the Fragile X Association of Georgia.
We didnt get the answers we were seeking until Scott
was diagnosed through genetic testing.
For
more than a decade, the Heymans have worked with Professor of
Human Genetics Stephanie Sherman and other researchers at Emory,
helping them to understand fragile X, which causes developmental
delays as well as problems with learning, motor skills, and
memory. Emorys fragile X program is one of the oldest
and most respected in the world.
Fragile
X is caused by a mutation in a single gene, as are cystic fibrosis,
sickle cell anemia, and hemophilia.
Everyone
has about five to ten mutations among the thousands of genes
they carry, says Sherman. Sometimes they cause problems,
or sometimes they are masked by the presence of other genes.
In
the late 1980s, Sherman noticed that fragile X syndrome did
not get passed on to offspring with the same probability as
most genetic disordersa phenomenon that became known as
the Sherman paradox.
In
1991, Department of Human Genetics Chair Stephen Warren (at
right with Stephanie Sherman) discovered the gene, FMR1, that
causes fragile X syndrome, and was among the first to develop
genetic tests to diagnose the disease. He also found that most
affected patients share a common genetic mutation called triplet
repeats, which helped to explain the Sherman paradox.
Warren recently created a new mouse model of fragile X syndrome
and is currently testing a variety of drugs on the genetically
altered mice.
About
4 to 5 percent of the population carry the gene for fragile
X, and about one in four thousand boys and one in eight thousand
girls have the syndrome. If one parent is a carrier, a child
has a chance of inheriting fragile X.
Most
people with fragile X syndrome will live a normal life span,
and their prognosis depends on the severity of the disability.
Scotts sister, Carly, has written a book, My eXtra Special
Brother, about her familys experiences.
Warren
is confident that with continued research, there soon will be
a therapeutic treatment for fragile X. Our involvement
with families like the Heymans, he says, make it
a very personal quest for us.M.J.L.
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