So, I’ve been obsessing for the last 24 hours about genetics, especially mine. I’ve learned a lot in the last day and am hoping to explain it to you.
I hear a lot about how there are more genes that we don’t know about in celiac that scientists are just starting to understand. A study just came out that “junk RNA” helps encode the for the inflammatory markers that can lead to celiac. Today we are going to talk about the alleles on the genes that are involved in Celiac.
Today, we know of two genes that are directly related to Celiac disease – HLA DQ2 and HLA DQ8. One of these markers is required for someone to develop Celiac disease. Without them, there is a less than 5% chance of developing Celiac. Of the genes there are variants – or alleles. These alleles are the details of how that particular gene functions.
If you have recently had a Celiac genetic test at the doctor, you probably got an allele report too. My report says, “Patient is HLA DQ2.5+ heterozyous. Positive for the HLA-DQ2.5 genotype. Patient carries one copy of the HLA-DQ2.5 genotype.” Now, I haven’t thought much of this, until I started looking into it.
It seems there are many different allele variations each with different implications for Celiac. The DQA1*02:01, DQB1*02, DQA1*05:01*, and DQB1*02 describe the specific alleles in my genetic makeup. My particular allele pattern encodes for the HLA-DQ2.5 genotype.
Different allele combinations define the different genotypes. There is HLA-DQ2.2, HLA-DQ2.3, HLA-DQ7.5, and some for DQ8. HLA DQ2.5 is more prone to getting full blown Celiac disease compared to someone with the HLA-DQ2.2 genotype. Also, I’ve seen in a couple of studies, but can’t really get a beat on it if those with HLA-DQ2.5 get more severe damage from Celiac or not.
Here’s why this is important. There are studies underway to determine if by using these genetic tests – with or without a gluten containing diet – if someone has Celiac disease. This could mean the end of endoscopic biopsies, gluten challenges, better more targeted medicines, or any medicine at all!
So, your genetic report from the doctor may have this level of detail. 23 and Me genetic testing just determines if you carry DQ2 or DQ8, not the details.
I’m not a doctor, nor do I have a medical degree. I’ve read a ton about this and am still working on understanding what the DQ2.5 heterozygous genotype means for me.
Link to wikipedia page describing DQ2.5.
Link to article talking about testing for different alleles and how it can be used.
Short abstract that started this journey.