The Science Behind Celiac Disease


When my younger sister was 10, our pediatrician noticed she was falling behind in the average height and weight for girls her age, and ran dozens of tests to determine the reason. That year, she was diagnosed with celiac disease. By definition, celiac disease is a disease in which the small intestine is hypersensitive to gluten, leading to difficulty in digesting food. If the word gluten means nothing to you, think of it this way: milk is to lactose-intolerant as wheat is to celiac disease. However, gluten is not just wheat, the term gluten applies to wheat, rye, and barley. Upon my sister’s diagnosis, my family had never heard of celiac disease, and we had no idea the tremendous lifestyle changes we would have to make to adapt to her newfound dietary restrictions.

According to the Celiac Disease Foundation (CDF) celiac disease is a hereditary autoimmune disorder that can occur in genetically predisposed people. Following the class lecture on what our genomes say about us, I was interested to find out more about celiac disease.

Just because my sister was the first person in our family to be diagnosed, that doesn’t mean she was the first person to have the disease. There are over 300 known symptoms associated with celiac disease, and the symptoms present themselves differently for everyone, while some people remain asymptomatic. Therefore, celiac disease may trace back through generations of my family members, but it could have easily been misdiagnosed, or gone undiagnosed. Genomes say a lot about our history, however, my families genetic history with celiac disease begins with my sister.

According to the CDF, celiac disease is estimated to affect 1 in 100 people worldwide. However, in the past decade there has been a sharp increase in the number of diagnoses.  Although there is a genetic component to the disease, the scientific community is stumped as to why some people with the gene get celiac and others don’t.  After my sister was diagnosed, I was tested for the disease. Although I carry the gene, I don’t have the disease. This information will be useful if I have kids, because the fact I carry the gene is an indication that my children will be at risk to inherit that gene and have the disease.

A personal anecdote i’ve noticed since coming to college is a change in my digestive patterns. I attribute this to the fact I am no longer eating a predominately wheat-free diet like I was at home. Although I do not have celiac disease, eating minimal amounts of wheat could have made me develop a gluten sensitivity, since my body was not regularly digesting it.

In our class discussion on what leads to the genetic mutations that cause cancer, we talked about the role that environmental factors play. If someone has the gene for lung cancer, it is very unlikely that they will develop lung cancer unless they also smoke. Similarly, with celiac disease: someone can have celiac disease, but not show any adverse symptoms if they don’t eat wheat in their diet. Both of these examples show that there can be strong environmental factor that can effect our genetics.

A study in the New England Journal of Medicine looked at the relationship between when gluten is introduced to a child’s diet, and their subsequent risk of celiac disease. The trial looked at early and delayed introduction of gluten to infant’s diet who had a genetic predisposition to the disease. The children in the trial, 832 in total, were monitored from birth. Following a randomization, the participating infants were then assigned to one of two groups: the first was fed food with gluten starting at six months, while the second were introduced to gluten starting at twelve months. Parents were interviewed to get information on their children’s diet and intestinal function and the total intake of gluten was determined with a dietary questionnaire. Each participant received a workup for celiac disease was performed at 15 months, 24 months, 3, 5, 8, and 10 years. The study concluded that delaying the introduction of gluten in a child’s diet had no effect on the risk of the long-term development of celiac. However, the study interestingly found that infants who were introduced to gluten at 12 months had a delayed onset of the disease.

This study could explain why my younger brother tested negatively for celiac disease. He is in the same boat my sister was when she was diagnosed, he’s 10 and is currently falling off his growth-chart. In order to avoid cross-contamination of gluten and gluten free foods, my entire family eats a gluten free diet at home. Meaning my younger brother had very minimal exposure to gluten from a young age following my sisters diagnosis. According to the study in the New England Journal of Medicine, this could cause a delayed onset of the disease. Additionally, our gluten free diet could explain why he doesn’t have adverse symptoms to wheat.

My family’s journey with celiac disease and a gluten free lifestyle is not unique. According to Dr. Sanjay Gupta, nearly 2 million Americans have celiac disease. I know that my genome tells me I carry the gene for celiac disease, but I’d be interested to find out what my SNP map would reveal.

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