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HEALTH

same reaction in individuals who lack genes encoding these immune reliable biomarker for celiac disease susceptibility, but emerging pro-
cell receptors. This explains why, even in ancient times, only a subset tein and genetic biomarkers may one day be clinically available for
of the population has been reported to develop GI symptoms from NCGS. Additionally, NCGS individuals may have a wheat allergy
gluten consumption. (WA) caused by an IgE mediated immune reaction to gluten as op-
Gluten Genetics: Using molecular genetic laboratory techniques, posed to the celiac specific T cell attack on the gut. Gluten is the
we can identify an individual’s inherited susceptibility to gluten in- least digestible, most immunogenic protein in the human diet so it
tolerance. DNA-based testing will identify the presence or absence comes as no surprise that the human immune system has multiple
of the genes encoding the gluten recognition immune cell receptors, ways to recognize and mount a targeted response against the gluten
HLA-DQ2 and DQ8. The receptors are comprised of two protein proteins. Human tissues including the gut, thyroid, and muscu-
chains, alpha and beta, (encoded by genes DQA1 and DQB1 re- loskeletal system are often in the line of fire and suffer collateral
spectively) that can be inherited from the same or different parents. damage through molecular mimicry when normal tissues are mis-
An estimated 30 percent of the human population carries combi- taken for gluten proteins.
nations of the DQ2 and DQ8 gluten intolerance susceptibility The Path to Wellness: Anyone with unexplained GI symptoms,
genes. Within this population of genetically susceptible individuals autoimmune disease, brain fog, chronic fatigue syndrome or known
there is a spectrum of elevated risk for developing severe celiac dis- celiac disease in a first degree relative could potentially benefit from
ease accompanied by 50 percent or 100 percent chance of trans- knowing their Gluten ID. In the direct to consumer (DTC) era of
mitting combinations of these genes to future generations. genetics, DQ2/DQ8 testing can be performed with cheek swab kits
Conversely, individuals lacking DQ2/DQ8 gene combinations have purchased online and results reported directly to the individual.
virtually no risk for development of celiac disease and 0 percent However, for purposes of wellness planning, it is desirable that
transmission risk. DQ2/DQ8 test results be included in the medical record. There-
Celiac Disease Testing: Prior to the Precision Medicine era, fore, Gluten ID testing is optimally ordered and performed by
clinical laboratory testing for celiac disease (the most extreme ex- physicians such as family practice or functional medicine, rheuma-
pression of gluten intolerance) has primarily been performed at the tologists, and gastroenterologists so it can be integrated into the pa-
protein (not DNA) level. Antibody-based tests including tTG-IgA tient’s preventive medicine and wellness plan. Gluten intolerance is
and IgA Endomysial antibody (EMA) remain the mainstays for lab- best viewed on a spectrum of risk, and those with the highest risk
oratory diagnosis because they are quick and accurate in acutely ill have increased incentive to be cautious about how much of a highly
patients who have been consuming gluten in their diet. immunogenic protein they introduce into their digestive system.
However, in individuals with celiac disease who are on a gluten Celiac and autoimmune diseases can be silent for many years, just
free diet and asymptomatic family members, antibody testing often like a glass gradually filling with water. However, as a glass overflows
gives false results because gluten antibodies are not being produced suddenly, so do celiac and autoimmune disease symptoms often
by the immune system. DNA testing thus provides a stable alterna- present without warning. Therefore, the path to wellness begins with
tive to antibody testing and only needs to be performed once in a knowledge about each person’s unique genetic predisposition to
person’s lifetime to provide accurate, unchanging results. DNA test gluten intolerance and continues through a lifetime of steps taken
results are often included with findings from antibody testing, clin- towards reducing risk and promoting health. In the era of person-
ical presentation, and small bowel biopsy to help make the diagnosis alized medicine, this pathway empowers each individual to know
of celiac disease. The high negative predictive value of DNA test their susceptibility and transmission risk for celiac disease in order
results essentially rules out the diagnosis of celiac disease in indi- to appropriately minimize gluten consumption and maximize a life-
viduals lacking the DQ2 and DQ8 genes. time of wellness.
Non-celiac Gluten Sensitivity (NCGS): For some individuals
with symptoms of gluten intolerance, genetic testing results are neg- References
ative for DQ2 and/or DQ8 genes. The good news for those with Chou, et al: Screening for celiac disease: a systematic review for
NCGS is their chances of developing severe celiac disease requiring the uS Preventive Services Task Force. March 2017, AHRQ publi-
small bowel biopsy is less than 1 percent. In addition, these individ- cation NO. 14-05215-EF-1.
uals have 0 percent chance of transmitting DQ2 and DQ8 genes Lebwohl B, et al: Celiac disease and non-celiac gluten sensitivity.
to their children. However, these positive factors do not diminish British Medical Journal 2015, 351:h4347
the reality of their gluten-related symptoms or detract from the im- Ludvisson JF, et al: Screening for celiac disease in the general pop-
portance of a gluten free diet as a path to wellness. DQ2 and DQ8 ulation and high-risk groups. United European Gastroenterology
positivity has been well documented in the medical literature as a Journal 2015, 3:106-120.

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