Coeliac disease, genetic risk

Clinical significance
Coeliac disease no longer appears as a rare condition with a single presentation, but as a varied clinical picture of gluten sensitivity found in many autoimmune and non-autoimmune diseases. Recent studies have reported a possible link between gluten enteropathy and clinical conditions affecting the reproductive system (infertility, recurrent miscarriages, oligo/azoospermia), neurological disorders (epilepsy, paraesthesia, peripheral neuropathy, early-onset dementia, cerebellar disease) and others (dermatitis herpetiformis, autoimmune thyroiditis, alopecia).
Mass screening has shown a genetically determined gluten intolerance in 1% of the population.
Many authors have shown that the HLA class II DQ2 and DQ8 types are present in over 90% of people with coeliac disease, compared with a frequency of about 25% in the general population. The presence of these haplotypes, detected by the genetic test, is enough to establish a person’s risk of developing the disease, and therefore whether they need to go on to the next diagnostic steps (blood tests and intestinal biopsy, which is of course invasive) to confirm the diagnosis.
The absence of the DQ2 and DQ8 haplotypes, shown by the genetic test, has a high, if not absolute, negative predictive value in the diagnosis of coeliac disease, as it reduces the chance of developing coeliac disease to 2%.