Don’t perform HLA genotyping in the presence of established diagnosis of celiac disease or for screening purpose.
HLA-DQ2/DQ8 genotyping is appropriate only in cases of uncertain diagnosis and in subjects with increased risk, like family members of celiac patients (to exclude from subsequent repeated controls the subjects who are negative) and patients with a disease implying an increased risk of celiac disease (such as diabetes mellitus type 1, selective IgA deficiency, autoimmune thyroiditis, hepatitis autoimmune, Down syndrome, Turner syndrome, Williams syndrome). The test has a limited diagnostic value, because the at risk HLA alleles are also frequent in the healthy population and they are not themselves sufficient to determine the disease, which appears only after exposure to environmental triggers and in the presence of other genetic factors. The analysis of HLA susceptibility genes has mainly a negative predictive value, as the absence of the alleles at risk makes very unlikely the development of the disease. The purpose of the test is to evaluate whether to continue the follow-up in selected cases.
1. Aress Regione Piemonte. Definizione dell’appropriatezza prescrittiva dei test genetici. http://www2.aress.piemonte.it/cms/progetti-terminati/category/159-progetti-terminati.html?download=573%3Adefinizione-dell-appropriatezza-prescrittiva-dei-test-genetici
2. Federazione Italiana Celiachia (FIC): Raccomandazioni Celiachia e Test HLA. http://www.celiachia.it/public/bo/upload/aic/doc/celiachia_hla_pdf_hr.pdf
3. SIGU: Raccomandazioni per esecuzione test HLA per celiachia.http://www.sigu.net/show/documenti/5/1/LINEE%20GUIDA%20SIGU
4. European Society for Pediatric Gastroenterology, Hepatology, and Nutrition guidelines for the diagnosis of coeliac disease.J Pediatr Gastroenterol Nutr 2012 Jan;54(1):136-60. Erratum in: J Pediatr Gastroenterol Nutr 2012 Apr; 54(4): 572.
Attention. Please note that these items are provided only for information and are not intended as a substitute for consultation with a clinician. Patients with any specific questions about the items on this list or their individual situation should consult their clinician.