lunes, 5 de noviembre de 2018

Coeliac Disease Screening

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By Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Cantab)

First degree relatives like parents, offspring and siblings are genetically at a higher risk of developing celiac disease. Second degree relatives are less so.

Celiac disease causes changes and damages to the inner linings of the small intestines due to presence of gluten in diet. Celiac disease may affect quality of life, raise risk of early death due to complications and risk of certain malignancies like small-bowel lymphomas, small-bowel adenocarcinomas, esophageal carcinoma, ulcerative jejunitis, refractory or untreatable celiac disease, enteropathy-associated T-cell lymphomas etc.

Thus screening for celiac disease is important. It meets the five World Health Organization criteria for justifying general screening in the population that include:-

Early detection could be difficult based on symptoms and signs alone
Common disorder causing significant morbidity in the general population
Availability of highly sensitive and specific tests
Available treatment
Lack of early detection may result in severe complications difficult to manage and raising risk of death

Screening for celiac disease

Screening for celiac disease looks at the presence of autoantibodies in the blood of susceptible individuals. Screening tests are not recommended routinely for all of the population but are advised in family members of a person with the disease.

At least 4 to 12 percent of an affected person’s first degree relatives will also have the disease.

Serologic tests look for three antibodies common in celiac disease:-

anti-tissue transglutaminase (tTG) antibodies
endomysial antibodies (EMA)
antigliadin antibodies (AGA)

The most sensitive antibody tests are of the immunoglobulin A (IgA) class, but immunoglobulin G (IgG) tests may be used in patients with IgA deficiency.

Usually panels of tests are used for screening. American Gastroenterological Association recommends beginning with tTG in the clinical setting.

Genetic screening

Another form of screening is with genetic screening tests. The gene pairs that encode for at least one of the human leukocyte antigen (HLA) gene variants, or alleles are called HLA‑DQ2 or HLA‑DQ8. These are found in about 40 percent of the general U.S. population, and most people with these alleles do not have celiac disease.

Negative findings for HLA-DQ2 and HLA-DQ8 can essentially rule out current or future risk of celiac disease.

Unlike serological testing, the genetic HLA testing measures the presence or absence of the genes. The HLA gene test for celiac disease can be performed at any time after birth while serological tests are positive after symptoms are positive.