|"The Food Doc" Dr. Scot Michael Lewey, D.O., FACP FAAP FACOP
An introduction to the genetics of Celiac and gluten sensitivity
There are many websites providing resources for those with Celiac Disease. Several
recommended links are provided on this site on the navigation bars on the left.
This autoimmune disorder occurs in 1/100 people worldwide who are genetically at risk. To
understand your risk for the genetically inherited chronic lifelong autoimmune disorder now
known as Celiac disease, Celiac Sprue or gluten sensitive enteropathy you need to know your
specific white blood cell HLA DQ type. This can be determined by a blood test or from a
sample of cells from a mouth swab. The genetics test is widely available but little known to
most doctors and patients. Some insurance companies do not pay for the test. The genetic
test does not diagnose Celiac but only determines if you have the genetic risk. It also does not
necessarily determine if you are sensitive or intolerant to gluten though many who have a
positive genetic test can exhibit some degree of intolerance to gluten derived from modern
wheat, barley or rye grains.
Almost all have a white blood cell pattern containing one or more inherited proteins types
designated as HLA DQ2 and DQ8. An individual can inherit either DQ2 or DQ8 from either
parent. The result is a white blood cell pattern that is HLA DQx/DQx where x can be a number
between one and nine.
Someone with two copies of DQ2 is termed homozygous and has the pattern DQ2/DQ2.
These individuals inherited a DQ2 from each parent and will pass a DQ2 to all their children.
They also carry the highest risk for Celiac disease and often have more severe disease.
Those who inherit only one copy of DQ2 from one parent and do not inherit a DQ8 from the
other parent are DQ2/DQx where x is not DQ2 nor DQ8. They are at less risk than those with
two copies but still carry a significant risk over those the general population.
One can inherit a DQ2 from one parent and a DQ8 from the other parent and would therefore
have a white blood cell HLA DQ pattern of DQ2/DQ8. Such individuals would pass either a
DQ2 or a DQ8 to each of their children who then would have at least one risk gene for Celiac
disease. Those with DQ2/DQ8 are higher risk for Celiac Sprue than those who only have one
copy of DQ2 or DQ8 but less risk than those who have two copies of DQ2, i.e. are DQ2/DQ2.
Those with only one copy of DQ8 but no DQ2 are still at an increased risk but less so than
those with any DQ2 or those with two copies of DQ8. Those with no DQ2 or DQ8 are
considered extremely low risk for Celiac Sprue but can be gluten intolerant. More information
can be found in my articles on genetics of Sprue that have been published on
www.celiac.com, in my blog the www.thefooddoc.blogspot.com or in the newsletter ScottFree.