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

As many of us are aware, even though identical twins have the very same 
DNA they do not always develop the same way. There are a number of 
researchers who have been exploring this and a number of their works 
relate to the phenomena of epigenetics and imprinted genes. Some of 
this work has developed  rapidly since the genome studies have been 
completed. Some of their work focuses on autoimmune diseases and 
diseases controlled by the  human major histocompatibility complex,  
which may sound a bell for people in the celiac world.

The epigenetics  theory is that there is a second genetic code beyond 
the ones we are familiar with. This code acts to silence or turn up the 
activity of genes. With identical twins one twin may have a gene 
silenced. Thus it would not take effect, or would take effect more 
slowly. The second code  would not show up on the usual DNA tests. 
Currently research is underway  the way to develop molecular diagnostic 
tests which would indicate what was operating.

The Imprinted gene theory suggests that  the outcome of genes may 
depend from which sex the gene is coming. If the gene comes from the 
mother it may silence a gene or the opposite while the father's gene 
will have a different effect even hough they are genetically the 
identical.   Much of this imprinting appears to happen before birth.  
If a gene is silenced it cannot counter the effect of the active  gene. 
  This leads to some of the known  genetic birth defects.  Also, with 
age,  the silencing gene, if it has a protective effect, may lose its 
power. Thus an illness may arise as a person gets older. ( People who 
hybridize plants have learned that it is important to plan which is to 
be the seed parent.)

I have tried to write this in a rather broad way .  It is based on some 
articles in the Wall Street Journal followed up by  internet searches 
on epigenetics and imprinted genes.

I feel that this has some very strong implications for the variable way 
celiac disease presents and why it may change over time.  If any one 
knows of researchers in the celiac  and refractive sprue worlds who are 
studying this area. I would like to learn about them.

Thank you in advance.
Sincerely,
Irma De Bruyn

Visit the Celiac Web Page at Http://www.enabling.org/ia/celiac/index.html
Archives are at: Http://Listserv.icors.org/SCRIPTS/WA-ICORS.EXE?LIST=CELIAC