If you have celiac disease, and you already have children or are planning to have children, you will be asking the question, “Will my children also have celiac disease?” Unfortunately, no one can actually answer that question definitively. What we do know is that relatives of people with gluten intolerance are more likely to be gluten intolerant. The more closely related, the more likely that two people will both be gluten intolerant. First degree relatives, which are parents, children, or siblings, have about an 11% chance of also having gluten sensitivity. So your children have an 11% chance of becoming gluten intolerant.
But there is no way to know if any of your children will be in those 11%. While there is clearly a genetic component to celiac disease, it is not straightforward; it is not inherited like eye color, for example. If one identical twin has celiac disease, 80% of the time, the other twin will also have it. However, fraternal twins have a much lower chance of sharing this condition, similar to the 11% risk of all first degree relatives.
When you look at the 80% of identical twins that share gluten intolerance, you have to wonder about the 20% that don’t. They have the same genes. Why don’t they both have intolerance 100% of the time? Similarly, what determines which one out of ten first-degree relatives of a person with celiac disease is going to have the illness?
The answer lies in the fact that gluten intolerance is multi-factorial. You do not just get it because of abnormal genes. Other things have to happen. In the most simple of terms, you could look at it this way – if you have all the genetic factors to tell your body you have gluten intolerance, but you somehow lived in a culture where gluten was not eaten, you would never get sick. At the very minimum, you must be exposed to gluten to actually have celiac disease. That may seem really obvious, but the exposure to gluten varies from culture to culture and family to family.
Back to the genetics of gluten sensitivity, it is known to be related to specific genes that code for HLA, or Human Leukocyte Antigens, with HLA-DQ2 and HLA-DQ8 accounting for 95% of the cases. Approximately 25% of people of European ancestry are HLA-DQ2 positive, yet only 4% of these develop gluten intolerance. The prevalence of gluten intolerance in persons of European ancestry is approximately 1%. Clearly something else is going on.
Gluten contains as many as 100 different proteins in its component glutenins and gliadins. It is not well digested, so that many different large pieces of gluten get down to the small bowel. It is there that they attach to HLA-DQ2 (or HLA-DQ8). These substances are presented to the immune system while attached to HLA antigens. They stimulate a type of T cells, immune cells that can release damaging chemicals. This begins a chain of events which makes the immune system attack intestinal epithelial cells, causing the damage seen in patients with celiac disease.
There are many steps in the sequence leading from gluten ingestion to intestinal damage. Some are well understood and some are not. The reasons why some people develop celiac disease and others do not are not completely clear.
It is believed that there are a number of other genes necessary, beyond HLA-DQ2 or HLA-DQ8 that must be present in order for gluten intolerance to develop. There must be another insult of some kind on the intestine that activates certain parts of the observed immune reaction in celiac disease. This may very well be infections by viruses that cause gastrointestinal disease, the kind of illness with vomiting and diarrhea that many children catch.
So, for your child to develop celiac disease, he or she must inherit a number of genes from you. These genes are not necessarily near each other on one chromosome and will not be passed on together. Additionally, other specific events must happen that as yet are poorly understood. If everything lines up in a certain way, your child may develop celiac disease. But more likely, he or she will not develop it.
Research in this area is very active and very interesting. Answers to some of the questions could have very practical applications. For example, does the age at which a child first eats wheat or gluten affect whether or not he or she will develop gluten intolerance? If the answer is yes, delaying the introduction of gluten into the diet might actually help prevent celiac disease. If you already eat a gluten-free diet, and decide to have children, it might not be difficult to keep your baby away from gluten.
So, although no one can tell you whether or not your child will develop celiac disease, the odds are 9 to 1 that he or she will not. Advances in understanding of gluten intolerance in the future may even give you tools to help prevent the disease, or minimize the disease, even if your children are genetically predisposed to have it.