Celiac Genetic Testing Answer Key

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  1. Why is the antibody test only useful if you are ingesting gluten?

The inflammation may be healed and the celiac antibodies may have disappeared if you are not ingesting gluten.  If you do not want to do a gluten challenge, your other option is celiac genetic testing. 

  1. What does the celiac genetic test detect?

It tests for certain variants of the HLA genes DQA and DQB. These are found on Chromosome 6, which is involved in our immune system and recognizing self and non-self-molecules. 

  1. Describe what you learned about the newly developed stool test.

There is a test that’s being developed that detects the gluten immunogenic peptides—they’re called GIPs—that are left in stool samples after digesting of gliadin. The test determines the level of these GIPs, so it’s a way to monitor whether gluten is still being eaten. The test detects very small amounts of gluten and studies have shown that 15% to 30% of patientsceliac patients in the studies on a self-reported celiac gluten-free dietstill have detectable amounts.

  1. True or False: DQA and DQB are HLA DQ genes specific to celiac?
    True. There are hundreds of variants of these two genes. Of these hundreds, two variants, DQ2 and DQ8, have alpha and beta chains on the surface of the immune cells that recognize and create an immune-mediated response. 
  1. What do DQ2 and DQ8 recognize that triggers celiac disease?
    Gliadin from gluten. 
  1. True or False: It is possible to inherit celiac disease from only one parent?
    True. Which gene variant? DQ2.
  1. What proportion of the general population carries DQ2 or DQ8? 30%. How many of them will develop celiac disease? 3%.
  1. True or False: Among people with celiac disease, more than 90% carry DQ2; approximately 2% to 10% carry DQ8, and the remainder carry only half of the DQ2 heterodimer.
    True. HLA variants relevant to celiac include DQ2 with both DQA1 05:01 or 05:05 AND DQB1 0201 or 0202. DQ8 is created if you have DQB1 03:02 AND DQA1 03.
  1. Is having both DQ2 and DQ8 a greater risk factor for developing celiac disease than having only one?
    Yes. 
  1. Does a negative HLA genetic test rule out celiac disease?
    Yes, it is 99.9% accurate and only needed once in a lifetime. 
  1. If you have a positive HLA genetic test, but do not show symptoms of celiac disease, should you get regular antibody screening?
    Yes. Celiac disease is very complex and can develop at various life stages.