This test provides complete genotyping of your DQA and DQB HLA protein chains and contains the following information:

• DQ2 genotyping (DQA1*0501, DQA1*0505 and DQB1*0201/*0202)
• DQ8 genotyping (DQB1*0302 and DQA1*03)
• ½ DQ2
• Homozygosity for DQB1*02

Sample Report

Celiac disease (CD) is caused by an immune response to gluten (a protein found in cereal grains) in genetically predisposed people. Although it is estimated that 1 out of 100 people are affected, fewer than 5% of those affected are actually diagnosed.^1,2 Failure to identify CD due to its variable non-specific symptoms and varying age of onset may result in in life long complications as well as secondary autoimmune disorders.^1,3

This genetic predisposition to develop CD is linked to human leukocyte antigen (HLA) class II alleles, in the HLA-DQ region of chromosome 6. The chart below gives the CD risk associated with the allele variants identified by this test.

The HLA-DQ2 allele has been found in about 95% of celiac cases, and HLA-DQ8 has been identified in nearly all 5% of the remaining cases. These HLA alleles are also found in 48-65% of first-degree relatives of people with CD and in up to 73% of people with insulin-dependent diabetes (type I diabetes) increasing these individual's risk of developing CD.⁴ Other high-risk groups who are likely to have these HLA alleles include people with autoimmune thyroiditis, rheumatoid arthritis, and IgA deficiency; as well as individuals with symptoms of unexplained iron deficiency anemia or premature-onset osteoporosis.^4,5 Sometimes celiac disease is triggered, or becomes active for the first time, after surgery, viral infection or severe emotional stress.

Instructions

The following document provides a full set of instructions for completing the test:

Instructions

Note

A positive result is not diagnostic for celiac disease. Positive results are indicative of a higher probability for celiac disease but need to be interpreted in the light of clinical symptoms and/or a small bowel biopsy.³ Negative results do not rule out the possibility of having celiac disease, they indicate an extremely low risk for development of the disease. Since DNA is being evaluated, this test is effective for people on a gluten-free diet. Additionally, this test only needs to be performed once since a person's genes do not change over time.

Results take 2-3 weeks from when specimen is received. This test is not available in Pennsylvania.

References

1. Green PHR, Cellier C, Celiac disease. N Engl J Med. 2007; 357:1731-1743
2. Green PHR. Mortality in Celiac Disease, intestinal inflammation and gluten sensitivity. JAMA. 2009; 302:1225-1226.
3. Snyder CL, Young DO, Green PHR, Taylor AK. Celiac disease. In: Pagon RA, Bird TC, Dolan CR, Stephens K, editors. GeneReviews (Internet), University of Washington, Seattle, July 3, 2008:1-27. Available at http://ncbi.nim.nih.gov/bookshelf/br.fcgi?book=gene&part=celiac. PMID 20301720 (PubMed)
4. Sollid LM. Coeliac disease: A complex inflammatory disorder. Nat Rev Immunol. 2002; 2:647-655.
5. Rostom A, Murray JA, Kagnoff MF. American Gastroenterological Association (AGA) Institute technical review on the diagnosis and management of celiac disease. Gastroenterology. 2006; 131:1981-2002.
6. Megiorni F, Mora B, Bonamico M, et al. HLA-DQ and risk gradient for celiac disease. Hum Immunol 2009; 70: 55-59
7. Pietzak MM, Schofield TC, McGinnis MF, and Nakamura RM. Stratifying risk for celiac disease in a large at-risk United States population by using HLA alleles. Clin Gastroenterol Hepatol 2009; 7: 966-971.