DQ2/DQ8 & HLA-DQ Risk Assessment For Celiac Disease
Celiac Disease is a chronic gluten-intolerance that occurs in genetically predisposed individuals. In gluten-sensitive individuals, the ingestion of gluten causes chronic inflammation of the small intestinal mucosa leading to villous atrophy and nutrient malabsorption. Celiac Disease DNA Testing can assess the genetic risk for developing the condition. The prevalence of Celiac Disease is estimated at about 1:100 in Caucasians, and it occurs more often in females with a gender ratio of about two-to-one. Furthermore, gluten intolerance is more frequent in at-risk groups, such as first-degree relatives of patients as well as individuals with specific genetic syndromes (Down, Turner, Williams) or autoimmune diseases (type I diabetes, thyroiditis and multiple sclerosis).
The signs and symptoms may vary between children & adults. Mild cases do not show any symptoms. Some of the common typical signs & symptoms of celiac disease include:
- Poor appetite
- Abdominal pain
- Weight loss
- Short stature
- Changes in mood such as anxiety
- Tingling numbness in the hands & feet
- Irregular periods, infertility or recurrent miscarriage
- Canker sores inside the mouth
- Thinning hair & dull skin
Most of the adults have symptoms unrelated to the digestive system such as:
- Osteoporosis (or) osteomalacia
- Blisters and skin rashes that itch
- Damage to the dental enamel
- Ulcers in the mouth
- Damage to the nervous system
- Ache in the joints and in the head
- Reduced functioning of the spleen (hyposplenism)
- Acid reflux & heartburn
The only way to manage this condition is to follow a strict gluten free diet.
- Life-long, strict gluten-free diet
- Lactose-free diet
- Daily multivitamin and calcium
- Folic acid for all women of child-bearing age
The following are foods that contain gluten and therefore, should be avoided:
- Graham flour
Some of the safe to eat gluten-free food for people with celiac disease:
- Fruit and vegetables
Celiac disease is a multifactorial disorder in which specific HLA-DQA1 and HLA-DQB1 alleles represent the major genetic predisposition. HLA typing allows a patient assessment of their relative risk. This means a positive test is indicative of genetic susceptibility but does not necessarily mean the disease is actively developing. A negative test result for Celiac Disease is just as informative, because gluten intolerance rarely occurs in the absence of specific HLA predisposing alleles. Approximately 90% of Celiac Disease patients possess DQA1*05 and DQB1*02(DQ2.5); 5-10% carry DQA1*03 and DQB1*0302 (DQ8); while about 5% of patients possess DQ2.x molecules, encoded by the DQB1*02 at-risk allele in the absence of the DQA1*05; and very rarely, Celiac Disease patients carry different DQ molecules (DQX.x).
The close association between Celiac Disease and these HLA alleles is due to the fact that these disease-associated HLA-DQ molecules expressed on antigen-presenting cells specifically bind gluten-derived peptides that are modified by the enzyme tissue transglutaminase (tTG) and present them to intestinal CD4+ T cells. The resulting T cell response leads to the production of auto-antibodies directed against tTG and to the secretion of pro-inflammatory cytokines (mainly TNF-α and IFN-γ) with consequent mucosa atrophy and clinical manifestations.
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- Karell et al. HLA types in celiac disease patients not carrying the DQA1*05-DQB1*02(DQ2) heterodimer: results from the European genetics cluster of celiac disease. Hum Immunol. 2003; 64:469-477