<<Disclaimer: Verify this information before applying it to your situation.>>

The recent post on identical twin risk for celiac disease raises an
important point on the gene(s) for celiac disease.

Identical twins are genetically identical.  They share all the same
genes.  If one has the gene(s) for a disease then the other has the same
genes.

The studies on the concordance of celiac disease between identical twins
suggests that it is less than 100% , more like 70%.  This tells us that
the disease does have a strong base in genes, but something else is
needed, some environmental factor to trigger the disease in a
genetically susceptible host.

On testing the gentically identical twin.  As the risk for celiac
disease so high (75%) in a seemingly unaffected twin a very careful
search for it should be made and the blood tests alone may not be
precise enough to rule it out entirely.

There is also a possibility that the twin may not have the disease at
this point but may develop it later in life and it may present
differently from the other twin.

The twin studies serve to illustrate the difference between a disease
that is strictly genetic in it nature and one that has a genetic
susceptibility.   many people can have the genes but never get the
disease.

This is not medical advice

Joseph Murray MD
Coordinator, Celiac Disease Clinic
University Of Iowa
Iowa City
IA 52242