SCD Research Section

  Genetics and Heredity       


Genetics and heredity have long been considered to be linked to Crohn's disease and ulcerative colitis. Independent studies by U.S. and French researchers announced on May 21st, 2001 the identification of a gene linked to Crohn's disease.



Announcement Summary       

"Crohn's disease appears to be caused by a mix of both inherited and environmental factors. One theory holds that the disease results from a faulty response to normal microbes found in the intestines, leading to an exaggerated immune response against the body's own tissue. The alterations in the Nod2 protein may explain part of what leads that immune response astray in some patients."

These findings (especially the faulty respone to intestinal microbes) concur with the research by Dr. S.V. Haas and Elaine Gottschall implicating microbial growth as a factor in causing Crohn's disease as well as their advocating the Specific Carbohydrate Diet in altering the microbial growth both qualitatively and quantitatively. The full findings relating to the identification of the gene will appear in the May 31, 2001 issue of Nature. Dr. Judy Cho, head of one of the research teams says, "We have long suspected that both genetics and the environment played a role in inflammatory bowel disease. This finally allows us to begin to understand how they work together to cause this disease."


Elaine Gottschall's Research Concurs       


It is well known among geneticists that genes plus environment can cause disease or result in health. The fact that scientists have located the gene only gives fuel to the new hype that we will soon be able to cure everything by injecting a virus carrying the correct gene. People should not continue to hype the idea that finding the gene is the b-all and end-all.

Finding this gene is only one part of a complex problem. For example, testing the DNA of Crohn's patients might show a "bad" gene but that gene CAN BE THE RESULT OF MALABSORPTION. This malabsorbtion has been researched by Dr. Haas and is discussed in Breaking The Vicious Cycle.

The building blocks of DNA require the formation of 4 base pairs (adenine, cytosine, thymine, guanine; ATCG) The cells cannot form thymine if the person is deficient in certain vitamins and minerals. All dividing and mutiplying cells are constantly forming these base pairs but if a person is deficient in certain vitamins and minerals (particularly folic acid and B12), they will not form the perfect molecule of thymine thereby resulting in a "bad" gene. With a thymine molecule that is not formed perfectly as cells divide, we have a mutation. Therefore, it is a vicious cycle of what comes first, the chicken and the egg.

(Not many people are aware of this but I took 3 years of genetics and did a graduate course in cytogenetics and gave a report on it. It is important to print the news of gene advances but it also important to give a fair shake to all science. Just being told that we are making advances so that we can someday inject a perfect gene into you to substitute for the bad gene is not enough.)

Dr. Ebringer's work has shown that genetically, (according to tissue typing) some people are more vulnerable to an attack against intestinal bacteria by the antibodies produced by the immune system. Dr. Ebringer showed about 15 years ago that histocompatibility genes (genes that confer on certain people a certain tissue type, eg. HbA-27) can make one susceptible to the antibodies that are trying to kill certain bacteria in the gut. He also showed how a diet similar to SCD got rid of the bacteria and stopped the immune system producing all those "lethal" antibodies.


Related Links       

Additional links to the article about chromosome 16 and the Nod2 protein:

The studies from both the U.S. and the French investigations will be published in the May 31 issue of Nature, which can also be accessed pre-publication here. You will need Abobe Acrobat Reader to read these two PDF files (you may view them in your browser or right-click and save them locally to view them later):

|  The French study: Association of NOD2 leucine-rich repeat variants with susceptibility to Crohn's disease (187k)

|  The American studies: A frameshift mutation in NOD2 associated with susceptibility to Crohn's disease (158k) Genetics of Crohn's disease and Faulty gene found..
ABC News: Hope for Crohn's disease
MSNBC: Mutant gene raises risk of Crohn's
Health-News: Crohn's disease gene identified
Nature: Genetics' Nod2 gut disease


And this helps       

One Usenet subscriber writes:

Interesting research, and no doubt promising for the future, but I don't see any practical result for us here-and-now IBDers.

We already know that, to avoid IBD, one should avoid being born with the "bad" genes, or, if you already have those genes, one should avoid ALL of the many triggers of the disease -- some known and some unknown -- for one's whole life.

It reminds me of Will Rogers' advice on the stock market:
"Buy a stock and, when it goes up, sell it. If it doesn't go up, don't buy it."