Celiac Genetics Test Questions

[RayB]

I've been feeling unhealthy, but most of my blood test results have been normal.  I feel worse (digestive and neurological symptoms) after eating gluten, and I did have a positive Endomysial Ab (IgA) Screen, so my doctor sent me to get blood work for HLA TYPING FOR CELIAC DISEASE.

I'm trying to figure out what my results mean.

HLA-DQ2 (DQA1*05/DQB1*02): Positive
HLA-DQ8 (DQA1*03/DQB1*0302): Negative

HLA-DQA1*: 02
HLA-DQA1*: 05
HLA-DQB1*: 0202
HLA-DQB1*: 0301

I've found several resources online that show any combination of (DQA1*05/DQB1*02) means DQ2.5, which is the most common combination for Celiac Disease.

Other resources I have found show that DQ2.5 requires HLA-DQA1*:0501 and HLA-DQB1*: 0201, which I don't have because I have HLA-DQB1*: 0202, and I don't know the last two digits of my second HLA-DQA1.

However, I found some resources that show HLA-DQA1*: 0505 and HLA-DQB1*: 0202 are also considered DQ2.5, which I also don't know if I have because don't know the last two digits of my second HLA-DQA1.

Then I found out that HLA-DQA1*: 0201 and HLA-DQB1*: 0202 means DQ2.2, which is a less common combination for Celiac Disease, which I also don't know if I have because I don't know the last two digits of my first HLA-DQA1.

So I'm wondering what conclusions I can even draw from these tests. I match the criteria for HLA-DQ2, but can I not determine anything more in depth because the blood tests only show two digits for both of my HLA-DQA1? I've been trying to research and understand, but there are so many resources online with either vague or conflicting information that it's overwhelming. I'm ignoring the HLA-DQB1*: 0301 since I don't think it's related, but I'm trying to figure out how the HLA-DQA1*: 02, HLA-DQA1*: 05, and HLA-DQB1*: 0202 can combine to form combinations that put me at different levels of risk from Celiac Disease.

I would appreciate if anyone can help my understanding of these results. Thank you!

[GFinDC]

Hi RayB,

The gene tests can't tell a person the have celiac disease.  Only that they are in the group that might get celiac disease.  The genes are actually fairly common, but celiac disease is much less common than the genes presence.

[frieze]

the money spent on gene testing should have been spent on complete celiac testing.  money poorly spent.  ask doc why he wanted it.  and pursue complete testing.

[RayB]

Thanks for the answers. I know very little about the science behind genes, but I've spent hours researching and trying to understand what the results of the test mean. It's discouraging to find out that they tell very little.

[cyclinglady]

Some 30% of the population has the genes that can develop into celiac disease, but that is a very few.  Gene testing is best to exclude celiac disease.  Somethines doctor's order it because they do not want to do an endoscopy.  Genes, positive blood tests and a trial diet helps lead to a diagnosis, but experts since prefer an endoscopy to obtain biopsies.  

You had a positive EMA.  That means you should be scheduled for an endoscopy.  Strange to run the one test that is the most expensive in the celiac panel (or it takes longer to get results?).  Learn more:

Open Original Shared Link

Open Original Shared Link

Keep eating gluten until all testing is done.  This is so critical!!!!,

[TexasJen]

This is from Quest Diagnostic, but it's pretty good....

Susceptibility to celiac disease is linked to certain human leukocyte antigen (HLA) class II alleles, especially in the HLA-DQ region. HLA molecules are postulated to present gluten antigens to T-cells which in turn induce tissue damage.2 Approximately 95% of patients with celiac disease have the HLA-DQ2 heterodimer encoded by the DQA1*05and DQB1*02 alleles, while close to 5% have the HLA-DQ8 heterodimer encoded by the DQA1*03 and DQB1*0302 alleles.1 Rarely, patients will carry only one of the DQ2 alleles; ie, either DQA1*05 or DQB1*02.3The HLA-DQ alleles are also found in 48% to 65% of first-degree relatives of patients with celiac disease and up to 73% of patients with insulin-dependent diabetes mellitus; thus, these individuals are at increased risk of developing celiac disease.1 Other high-risk groups include those with autoimmune thyroiditis; Down, Turner, or Williams syndrome; selective IgA deficiency; or individuals with symptoms of unexplained iron deficiency anemia or premature-onset osteoporosis.1,4 Since 25% to 40% of the United States population has either DQ2 or DQ8, the presence of either heterodimer is not diagnostic of celiac disease.1 Thus, the primary use of HLA-DQ typing is to rule out celiac disease and genetic susceptibility for celiac disease. Such typing is particularly relevant when pathology of the small intestine is equivocal, serological testing is consistent with celiac disease but villous atrophy is absent, a gluten-free diet is being considered in the absence of biopsy-proven celiac disease, and a first-degree relative has been diagnosed with celiac disease.5 Determining genetic susceptibility can avoid unnecessary small intestine biopsy, continual serologic testing, and initiation of a gluten-free diet, especially in individuals in high-risk groups.1,4

I think your doc did it to rule out celiac - meaning IF it had been NEGATIVE it would have been helpful. Then he/she could say definitively that you don't have celiac. But, since it's positive, it's not particularly helpful. You need more information now to confirm or rule out the diagnosis of celiac. And, as cycling lady said, that's probably an endoscopy.