Scleroderma and Genetics
By Alan W. Friedman, M.D., University of Texas/Houston, Health
Science Center, Dept. of Internal Medicine/Rheumatology (originally
published in "Scleroderma Voice," 2001 #4)
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Alan
W. Friedman, M.D. |
Question: I am looking for answers as to whether there
is a genetic/hereditary component to scleroderma. My 66-year-old
husband died from CREST last year. I have a 37-year-old son,
so of course I am concerned about the chance scleroderma could
be inherited by him.
Answer: While scleroderma
has generally been considered to be a disease that is not
inherited, our studies at the University of Texas Houston
Medical School suggest this is incorrect.
We have a very large database of scleroderma patients on
whom we have complete genetic and clinical data, and the frequency
of scleroderma in some member of their family (first-degree
relative—meaning parent, brother, or sister) is roughly
1.5%.
This is far greater than the frequency in the general population
(approximately 30 per 100,000 or 0.003%), which is strong
evidence that this is either due to genetic transmission or
a common environmental cause. There are really no hints that
our patients had an unusual environmental exposure, which
leaves genetics as the common factor.
We have also studied the Choctaw Indians in southeastern
Oklahoma, where those who are full-blooded (no non-Choctaw
blood going back as far as their records can go) have a frequency
of scleroderma of 469 individuals per 100,000 (over 15 times
the rate of the general population). This is also very strong
evidence for a genetic effect, and extensive evaluations for
an environmental cause have been unrevealing.
With regard to your son, our studies suggest that people
with a family history of scleroderma have a risk of developing
the disease that is 10–16 times higher than normal, but
this is still quite low since scleroderma is a relatively
rare disease. |
