DNA testing for celiac testing and gluten challenge

[LaureP]

Hello,

First, I want to apologize for my English, I am not a native speaker.

I would like to know your opinion about DNA testing for genes associated with celiac disease. I believe I have a problem with gluten/wheat but I don’t know if it’s celiac disease or just non celiac wheat/gluten sensitivity and I would like to do a genetic test to know if I have one of the genes associated with celiac disease, in this case I would to a gluten challenge. If it turns out that I have none of these genes, I would consider it’s rather non celiac sensitivity.

Are the genetic home tests accurate? Would you recommend me a specific company? I read that saliva sample are more accurate than mouth swab, but I don’t know if this is true. The two home tests I looked at are those of 23 rd and me and Genovate.

https://www.23andme.com/dna-health-ancestry/ 

https://www.genovate.com/product/dna-celiac-test/ 

I also want to ask my doctor to do a genetic test but I live in France and my country is very restrictive and conservative about genetic testing, so I guess the answer will just be “no, do a gluten challenge instead”…

I read that https://nationalceliac.org/celiac-disease-questions/ancestry-type-testing-for-celiac-genes/   

And the sentence “Rarely, people with only 1/2 of the DQ2 gene (ie. DQ2.2, DQ2.5 or DR5) will get celiac disease but this occurs in <5% of people with celiac disease.1 If the genetic test used does not have the ability to “look for” and identify all of these possible variations,  the consumer may receive inaccurate test results »frightened me a little bit… genetic testing seems to be a complex topic!

Do home genetic test detect those variants?

I am now 29 and I realized I had a problem with wheat/gluten when I was 22. I had a lot of acne and I discovered that eating less gluten improved my skin greatly. I can still get acne under the influence of my hormones, for instance in the ovulatory phase of my cycle, but there is a big difference between getting 4-5 pimples and getting 30 or more…

Back then I didn’t know what was celiac disease and I just reduced dramatically the amount of wheat/gluten in my diet, but I have never been strictly gluten free (I used to eat some gluten when eating out or travelling).

Family : no family history of celiac disease, but my dad who has a lot of digestive issues (bloating, etc.) + joint paint, still eats gluten, has agreed to do the antigenic blood test.

Other symptoms I have that may be related to gluten/wheat

-       Mouth ulcers, seem to improve while on a gluten free diet

-       Dental enamel erosions : teeth becoming transparent, showing the dentin + small brown spots on two incisors, a big brown spot on one molar. I have been told by the dentist that the spots were the result of my tea and coffee consumption. Could I post pictures to have your opinion? I was surprised to discover that celiac disease could cause dental problems, I had never heard of that… nor my dentist, I guess :/ 

-       Reflux : I did a ph-impedance-monitoring and I have been told that I have “non acidic reflux” (PH above 4) and that it was not dangerous, not taking currently any medication, but I feel it sometimes in my throat.

-       Belching : constant belching after eating

-       Chronic diarrhea : doesn’t improve on a gluten free diet, must be the result of SIBO

-       SIBO : diagnosed 2 months ago via lactulose breath test, positive for both hydrogen and methane. I haven’t treated it yet, I need to figure out first if I have an underlying issue with gluten, since people with celiac disease are at risk for SIBO.

 

Other details about my health

-       I have a diagnosis of ASD (autism spectrum disorder) and ADHD, both seem to increase the risk of celiac disease (and SIBO)

-       I am underweight, 46 kg for 1m64

-       Last blook work show vitamin D deficiency (improved after supplementing), low iron (but not deficient), normal vit B12, normal-low vit B9, iodine deficiency, low cholesterol (both HDL and LDL)

 

Gluten challenge 2021

I did a previous gluten challenge in april-may 2021, I only did 6 weeks but now I read that it could be better to do 3 months… https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3847752/

I was eating gluten on a daily basis during those 6 weeks, but maybe I wasn’t eating enough, I hadn’t read the “4 to 6 slices of bread” info.

After six weeks, I had a blood test for anti-ttg antibodies, result was negative : < 3 U/mL, results considered negative by the lab if > 7 U/mL

But the doctor never ordered the total IGA = if I am deficient in IGA, this test was not accurate…

I had an endoscopy but the gastro-enterologist only took 1 sample of biopsy in my duodenum, and it was normal. But now I read that the norm is to take 4 to 6 samples to detect the lesions…

 

What is a complete blood test to detect celiac disease ?

Can I take supplements while doing the gluten challenge? I usually take : iodine, vitamin D, omega 3, magnesium. Could it change the results?

Sorry for writing such a long message! In 2021 when I was told by my doctors that I didn’t have celiac disease, I believed them, now, when I look back, I think the procedure was not 100 % reliable…

Any thoughts, comments would be welcome

Best regards,

[trents]

4 hours ago, LaureP said:

Hello,

First, I want to apologize for my English, I am not a native speaker.

I would like to know your opinion about DNA testing for genes associated with celiac disease. I believe I have a problem with gluten/wheat but I don’t know if it’s celiac disease or just non celiac wheat/gluten sensitivity and I would like to do a genetic test to know if I have one of the genes associated with celiac disease, in this case I would to a gluten challenge. If it turns out that I have none of these genes, I would consider it’s rather non celiac sensitivity.

Are the genetic home tests accurate? Would you recommend me a specific company? I read that saliva sample are more accurate than mouth swab, but I don’t know if this is true. The two home tests I looked at are those of 23 rd and me and Genovate.

https://www.23andme.com/dna-health-ancestry/ 

https://www.genovate.com/product/dna-celiac-test/ 

I also want to ask my doctor to do a genetic test but I live in France and my country is very restrictive and conservative about genetic testing, so I guess the answer will just be “no, do a gluten challenge instead”…

I read that https://nationalceliac.org/celiac-disease-questions/ancestry-type-testing-for-celiac-genes/   

And the sentence “Rarely, people with only 1/2 of the DQ2 gene (ie. DQ2.2, DQ2.5 or DR5) will get celiac disease but this occurs in <5% of people with celiac disease.1 If the genetic test used does not have the ability to “look for” and identify all of these possible variations,  the consumer may receive inaccurate test results »frightened me a little bit… genetic testing seems to be a complex topic!

Do home genetic test detect those variants?

I am now 29 and I realized I had a problem with wheat/gluten when I was 22. I had a lot of acne and I discovered that eating less gluten improved my skin greatly. I can still get acne under the influence of my hormones, for instance in the ovulatory phase of my cycle, but there is a big difference between getting 4-5 pimples and getting 30 or more…

Back then I didn’t know what was celiac disease and I just reduced dramatically the amount of wheat/gluten in my diet, but I have never been strictly gluten free (I used to eat some gluten when eating out or travelling).

Family : no family history of celiac disease, but my dad who has a lot of digestive issues (bloating, etc.) + joint paint, still eats gluten, has agreed to do the antigenic blood test.

Other symptoms I have that may be related to gluten/wheat

-       Mouth ulcers, seem to improve while on a gluten free diet

-       Dental enamel erosions : teeth becoming transparent, showing the dentin + small brown spots on two incisors, a big brown spot on one molar. I have been told by the dentist that the spots were the result of my tea and coffee consumption. Could I post pictures to have your opinion? I was surprised to discover that celiac disease could cause dental problems, I had never heard of that… nor my dentist, I guess 😕

-       Reflux : I did a ph-impedance-monitoring and I have been told that I have “non acidic reflux” (PH above 4) and that it was not dangerous, not taking currently any medication, but I feel it sometimes in my throat.

-       Belching : constant belching after eating

-       Chronic diarrhea : doesn’t improve on a gluten free diet, must be the result of SIBO

-       SIBO : diagnosed 2 months ago via lactulose breath test, positive for both hydrogen and methane. I haven’t treated it yet, I need to figure out first if I have an underlying issue with gluten, since people with celiac disease are at risk for SIBO.

 

Other details about my health

-       I have a diagnosis of ASD (autism spectrum disorder) and ADHD, both seem to increase the risk of celiac disease (and SIBO)

-       I am underweight, 46 kg for 1m64

-       Last blook work show vitamin D deficiency (improved after supplementing), low iron (but not deficient), normal vit B12, normal-low vit B9, iodine deficiency, low cholesterol (both HDL and LDL)

 

Gluten challenge 2021

I did a previous gluten challenge in april-may 2021, I only did 6 weeks but now I read that it could be better to do 3 months… https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3847752/

I was eating gluten on a daily basis during those 6 weeks, but maybe I wasn’t eating enough, I hadn’t read the “4 to 6 slices of bread” info.

After six weeks, I had a blood test for anti-ttg antibodies, result was negative : < 3 U/mL, results considered negative by the lab if > 7 U/mL

But the doctor never ordered the total IGA = if I am deficient in IGA, this test was not accurate…

I had an endoscopy but the gastro-enterologist only took 1 sample of biopsy in my duodenum, and it was normal. But now I read that the norm is to take 4 to 6 samples to detect the lesions…

 

What is a complete blood test to detect celiac disease ?

Can I take supplements while doing the gluten challenge? I usually take : iodine, vitamin D, omega 3, magnesium. Could it change the results?

Sorry for writing such a long message! In 2021 when I was told by my doctors that I didn’t have celiac disease, I believed them, now, when I look back, I think the procedure was not 100 % reliable…

Any thoughts, comments would be welcome

Best regards,

Welcome to the forum, LaureP!

Supplements will not affect antibody testing for celiac disease.

The Mayo Clinic recommends the consumption of two slices of wheat bread (or the gluten equivalent) daily for 6-8 weeks pretest.

A complete celiac antibody panel would consist of total IGA, tTG-IGA, Deamidated gliadin peptide (DGP IgA and IgG) and IgA Endomysial antibody (EMA): https://celiac.org/about-celiac-disease/screening-and-diagnosis/screening/

The GI doc should take at least four samples from both the duodenum and the duodenum bulb. Damage can be patchy.

[Scott Adams]

I believe 23 and Me will test for all know makers for celiac disease, but am not 100% sure about that. You may need to contact them to verify this.

[LaureP]

Hello !

Thank you very much for your answers !  

On 8/14/2022 at 9:30 PM, Scott Adams said:

I believe 23 and Me will test for all know makers for celiac disease, but am not 100% sure about that. You may need to contact them to verify this.

Scott Adams, I emailed 23 and me and this is what they say :

"The Celiac Disease genetic health risk report (i) is indicated for reporting of the rs2187668 variant in the HLA-DQA1 gene, which tags the HLA-DQ2.5 haplotype; and the rs7454108 variant near the HLA-DQB1 gene, which tags the HLA-DQ8 haplotype, (ii) describes if a person has variants associated with a higher risk of developing celiac disease. (iii) The variants included in this test are most common and best studied in people of European descent"

Is it ok ? I don't really understand if this tests looks at all known variants associated with celiac disease.

For the other DNA test I looked at, Genovate write on their website the following :

"This DNA test detects nucleotide changes that occur in the three celiac disease-associated alleles of the HLA-DQA1 and HLA-DQB1 genes (HLA-DQA1*05, HLA-DQB1*02, HLA-DQB1*0302).These celiac disease-associated variants can also pair together to form proteins known as DQ2 and DQ8. The presence or absence of these variants gives an indication of the risk of gluten sensitivity and celiac disease." https://www.genovate.com/product/dna-celiac-test/ 

Trents, even digestive enzymes supplements will not affect antibody testing for celiac disease ?

Thank you for the list of antibodies!  is it useful to test also for IGG endomysial antibody (EMA) ?

As for the endoscopy, is it possible to be celiac and to test negative for all these different antibodies? I mean, is the endoscopy necessary if I test negative after a long 3 months gluten challenge?

On 8/14/2022 at 6:28 PM, trents said:

Welcome to the forum, LaureP!

Supplements will not affect antibody testing for celiac disease.

The Mayo Clinic recommends the consumption of two slices of wheat bread (or the gluten equivalent) daily for 6-8 weeks pretest.

A complete celiac antibody panel would consist of total IGA, tTG-IGA, Deamidated gliadin peptide (DGP IgA and IgG) and IgA Endomysial antibody (EMA): https://celiac.org/about-celiac-disease/screening-and-diagnosis/screening/

The GI doc should take at least four samples from both the duodenum and the duodenum bulb. Damage can be patchy.

Thank you so much for sharing this information, I am very glad I found this forum  

Best regards,

Laure

[LaureP]

And the same question about tTG antibodies : is it useful to test also for IGG tTG antibodies, not just IGA tTG ?

Thank you

[LaureP]

And what do you think of testing for anti reticulin antibodies?

It seems to be obsolete https://www.researchgate.net/publication/235386355_Testing_for_Anti-reticulin_Antibodies_in_Celiac_Disease_is_Obsolete_A_Review_of_Recommendations_for_Serologic_Screening_and_the_Literature 

Thank you  

[LaureP]

And I guess that "Deamidated gliadin peptide (DGP IgA and IgG)" antibody is not the same as "Gliadin antibody" ?

Sorry, I am looking at the translations of these antibody names in French so that I know what I have to ask my doctor

Best regards,

Laure

[trents]

12 minutes ago, LaureP said:

And the same question about tTG antibodies : is it useful to test also for IGG tTG antibodies, not just IGA tTG ?

Thank you

Yes it is.

 

12 minutes ago, LaureP said:

And the same question about tTG antibodies : is it useful to test also for IGG tTG antibodies, not just IGA tTG ?

Thank you

Yes it is.

[trents]

4 minutes ago, LaureP said:

And I guess that "Deamidated gliadin peptide (DGP IgA and IgG)" antibody is not the same as "Gliadin antibody" ?

Sorry, I am looking at the translations of these antibody names in French so that I know what I have to ask my doctor

Best regards,

Laure

No, I think it's the same.

 

15 minutes ago, LaureP said:

And the same question about tTG antibodies : is it useful to test also for IGG tTG antibodies, not just IGA tTG ?

Thank you

Yes it is.

[trents]

Digestive enzymes should not affect your antibody testing.

EMA is a valuable test but is an expensive one. It is not considered very sensitive but it is very specific for celiac disease. So, if you test positive for this one it pretty much removes any doubt that you have celiac disease.

It is always better to get a complete celiac panel done with all applicable antibody tests than just one or two. Less chance of missing those whose immunes system response is atypical. 20% of white people with celiac disease (biopsy confirmed) will test negative when only the tTG-IGA is ordered and 80% of blacks will be missed.

Edited August 20, 2022 by trents

[Scott Adams]

21 hours ago, LaureP said:

Scott Adams, I emailed 23 and me and this is what they say :

"The Celiac Disease genetic health risk report (i) is indicated for reporting of the rs2187668 variant in the HLA-DQA1 gene, which tags the HLA-DQ2.5 haplotype; and the rs7454108 variant near the HLA-DQB1 gene, which tags the HLA-DQ8 haplotype, (ii) describes if a person has variants associated with a higher risk of developing celiac disease. (iii) The variants included in this test are most common and best studied in people of European descent"

Is it ok ? I don't really understand if this tests looks at all known variants associated with celiac disease.

For the other DNA test I looked at, Genovate write on their website the following :

"This DNA test detects nucleotide changes that occur in the three celiac disease-associated alleles of the HLA-DQA1 and HLA-DQB1 genes (HLA-DQA1*05, HLA-DQB1*02, HLA-DQB1*0302).These celiac disease-associated variants can also pair together to form proteins known as DQ2 and DQ8. The presence or absence of these variants gives an indication of the risk of gluten sensitivity and celiac disease." https://www.genovate.com/product/dna-celiac-test/ 

I can't claim to be fully up on every genetic variant that could make celiac disease more likely, but it looks like going with either of these should be enough, and perhaps Genovate might be slightly better. There are upsides and downsides to doing it with 23 and Me, for example privacy issues regarding your test results, but the upsides are getting all of your genetic family tree history, and possible connections to relatives you didn't know you had.

[LaureP]

Thank you so much for your answers Trents and Scott Adams ! It is very helpful to me

[LaureP]

18 hours ago, Scott Adams said:

I can't claim to be fully up on every genetic variant that could make celiac disease more likely, but it looks like going with either of these should be enough, and perhaps Genovate might be slightly better. There are upsides and downsides to doing it with 23 and Me, for example privacy issues regarding your test results, but the upsides are getting all of your genetic family tree history, and possible connections to relatives you didn't know you had.

Thank you ! I am having trouble getting the 23 and Me genetic kit because I live in France and my country has a very restrictive policy about genetic testing. I have emailed Genovate but I haven't received any reply yet.

I have found another company that offers a DNA test for celiac disease. It's EasyDNA, they could send the kit to me from the UK. 

What do you think about this test ? https://easydna.co.uk/celiac-disease-genetic-testing/#

They provide an example of a report, I have put the image below.

Thank you

Best regards,

Laure

[trents]

1 hour ago, LaureP said:

Thank you ! I am having trouble getting the 23 and Me genetic kit because I live in France and my country has a very restrictive policy about genetic testing. I have emailed Genovate but I haven't received any reply yet.

I have found another company that offers a DNA test for celiac disease. It's EasyDNA, they could send the kit to me from the UK. 

What do you think about this test ? https://easydna.co.uk/celiac-disease-genetic-testing/#

They provide an example of a report, I have put the image below.

Thank you

Best regards,

Laure

That looks like a good option if you only want to check for celiac genes. The way they have laid it out in table form is very simple with the last column on the right being what you really want to know. It doesn't have excessive information that can be confusing.

[LaureP]

Hey !

I am back on this forum since I need some advice, again ^^

Finally, I haven't been able to order any genetic test since my country (France) has very restrictive policies about genetic testing. But I convinced my gastroenterologist to do it here in a hospital, we're waiting for the results (it's long 😕).

He wants me to do an endoscopy anyway since I may have a gastritis due to covid (my stomach hurts a lot since I have had covid). He wants me to do a gluten challenge so that he can take biopsies from my duodenum to check for celiac also. The endoscopy would be in 4 weeks, is that long enough for a gluten challenge ? I read somewhere that doing an endoscopy after 2 weeks eating gluten was still worth. How much gluten do I have to consume daily ? Can I have sourdough bread ? I read somewhere that it contains less gluten so I don't really know how to monitor my gluten challenge with sourdough bread, but I hate regular bread, it gives me lot of bloating. I tolerate better sourdough bread.

(I have been restricting gluten for 7 years, not completely gluten free, but restricting it a lot. I have been eating gluten 3 weeks this summer, but I haven't eaten gluten since august 30th, when my stomach symptoms worsened).

I am also taking different medications and supplements to help me with my stomach pain and burning. Could they interfere with the biopsies results ? Some of them are supposed to help with my gastric lining, so I thought maybe they could prevent the flattened villies to appear in the duodenum. Zinc Carnosine and L Glutamine especially are supposed to heal the intestinal lining as well as the gastric lining. Here's what I am currently taking : 

- pantoprazole 40 mg (proton pump inhibitor)

- DGL (Deglycyrrhizinated Licorice)

- aloe vera, slippery elm, marshmallow root

- Zinc carnosine

- L Glutamine

- raw cabbage juice

My Anti-transglutaminase antibodies (IGA) were negative last year after a six weeks gluten challenge (but I am not sure I was eating enough gluten). Total IGA have been done a month ago, they are normal.

Actually, the main reason we are doing the endoscopy is to check for stomach inflammation after covid. But I think it's a good thing to check for celiac at the same time since I have had trouble with gluten  for years (gives me acne, worsens my IBS symptoms, etc.). I want to be sure I do the gluten challenge correctly so that the biopsies results are valid.

Thank you for your advice

Best regards,

Laure

[trents]

The Mayo Clinic guidelines for a gluten challenge leading up to the endoscopy/biopsy is two slices of wheat bread daily (or the gluten equivalent) for at least two weeks prior to the procedure. Four weeks should be plenty good. I would make those two slices regular wheat bread and not sourdough as the fermentation process that creates the tangy taste in sourdough bread alters some of the gluten. If you want to use sourdough bread, make that in addition to the two slices of regular wheat bread.

If I were you I would not take a PPI on a long term basis as it increases the stomach PH (decreases acidity) and will interfere with the digestion of foods and nutrient availability. Concerning licorice, I assume you are taking the extract or the bare root and not eating licorice sticks candy. Licorice candy is made with wheat paste.

Edited October 19, 2022 by trents

[LaureP]

1 hour ago, trents said:

The Mayo Clinic guidelines for a gluten challenge leading up to the endoscopy/biopsy is two slices of wheat bread daily (or the gluten equivalent) for at least two weeks prior to the procedure. Four weeks should be plenty good. I would make those two slices regular wheat bread and not sourdough as the fermentation process that creates the tangy taste in sourdough bread alters some of the gluten. If you want to use sourdough bread, make that in addition to the two slices of regular wheat bread.

If I were you I would not take a PPI on a long term basis as it increases the stomach PH (decreases acidity) and will interfere with the digestion of foods and nutrient availability. Concerning licorice, I assume you are taking the extract or the bare root and not eating licorice sticks candy. Licorice candy is made with wheat paste.

Hello !

Thank you for your answer. I will do the gluten challenge as you say !

I don't want to take the PPI long term, I know it's really bad. My stomach pain after covid was so intense that I had no choice, or I couldn't even sleep. I hope the endoscopy will help me find what I have to that I can switch to other solutions. It's probably gastritis. DGL is a licorice extract without the component that can cause high blood pressure, it is supposed to coat the stomach lining to protect it, and no, I don't take it as a candy

Best regards