Confusing Genetic Test Results - Help!

[greenbeanie]

I seem to be one of those people with test results that are always confusing. I'd thought I understood how genetic tests work, but the interpretation on the form from Prometheus Labs does not match other things I'd read. My results:

 

"One allele (HLA DQA1.05) detected of DQ2.5 halotype detected. HLA DQB1.02 not detected." That made sense so far...but then the overall assessment is "DQ2.5 negative, DQ8 negative." 

 

I understand that I don't have the DQ8 gene. But what on earth does the first sentence mean? It's saying that have one allele of the DQ2.5 gene, but that I don't have the gene itself?? Isn't having a gene just a matter of having alleles of that gene?

 

I feel like I'm on a merry-go-round here. My symptoms are extremely strong, life-long, and well-documented. My blood tests were negative, although it was only a partial panel and I wasn't checked for IgA deficiency. My daughter just got clear positive celiac results from all three tests on the panel they ran. They did not test her genes. I have anti-nuclear antibodies, which I understand is a non-specific indicator of autoimmune diseases, though some people also have it for no apparent reason. The things I've read seem to indicate that having DQA1.05 of the DQ2.5 halotype is strongly associated with celiac - but Prometheus' overall assessment is that I'm at extremely low risk for celiac because I don't have the DQ2.5 gene. So, so confused...

 

 

 

 

 

 

[1desperateladysaved]

I would inquire of whoever did the test and of the lab that did it.  They should interpret their results.  The company I worked with sent explanations with the results and also I contacted them by e-mail.

[stanleymonkey]

It may be a resessive allele, you may need 2 of them for it to be dominant therefore having just one and one of another means it is resessive therefore irrelevant.

Eg 2.5 and another 2.5 would be positive genetics for celic but 2.5 and 2.6 2.6 is dominant so the 2.5 genetic material has no impact ( don't know if there really s a 2.6 but thought it might help explain!)

[ravenwoodglass]

Celiac is neither recessive or dominant so people can develop celiac with only one copy of a gene. Do keep in mind that many labs, including it appears this one only check for the 2 most common celiac associated genes. Some research shows that there are many more associated than just these two. You can have celiac and not have either of them and you can have copies of both and not have celiac. While interesting gene testing cannot fully rule celiac in or out.

[pricklypear1971]

Genes are comprised of alleles. Sounds like you have HALF of the 2.5 gene. You have zero alleles of the dq8 gene.

The report says negative because you don't have the full gene (which is stupid). You have one half of a Celiac gene. It's enough. I have two halves: half dq2.5, half dq8.

[stanleymonkey]

There as been recent research at Louisiana state into dominant genes and celiac disease, they have drawn links between certain genes and dominance any Irish ancestry. Our immunologist knows someone who did some of the research.

, I'll try and figure out how to post the link

[greenbeanie]

Thanks, everyone. That makes sense, pricklypear: I have half of a celiac gene. I need to brush up on my chemistry and biology...

I am 1/4 Irish. I'd be interested in that article, stanleymonkey, if you happen to come across the link.

Prometheus Labs, unfortunately, will not discuss results with patients and will only release the info to doctors. I hadn't even realized that my doctor ordered the genetic tests. I hope that the half-DQ2.5 gene plus symptoms will be enough to get the GI to do an endoscopy. I'm glad my daughter is ahead of me in the diagnostic process - it should help my doctor to take this seriously if I go in with documentation that a first-degree relative has celiac.

[pricklypear1971]

Thanks, everyone. That makes sense, pricklypear: I have half of a celiac gene. I need to brush up on my chemistry and biology...

I am 1/4 Irish. I'd be interested in that article, stanleymonkey, if you happen to come across the link.

Prometheus Labs, unfortunately, will not discuss results with patients and will only release the info to doctors. I hadn't even realized that my doctor ordered the genetic tests. I hope that the half-DQ2.5 gene plus symptoms will be enough to get the GI to do an endoscopy. I'm glad my daughter is ahead of me in the diagnostic process - it should help my doctor to take this seriously if I go in with documentation that a first-degree relative has celiac.

Remember, she can get more genes from Dad. My son has half a gene from Dad that I don't have...which leaves the question if hubs has a whole gene....

And I wouldn't do gene testing on your daughter yet - some docs will EXCLUDE celiac if the gene test isn't fully positive. So, it can work against her.