Fequency distribution of HLA DQ2 and DQ8 in celiac patients and first-degree relatives in Recife, northeastern Brazil

Abstract

AIMS:The aim of this study was to evaluate the frequencies of the HLA genotypes DQ2 and DQ8 and the alleles A1*05, A1*0201, B1*0201 and B1*0302 in individuals with celiac disease in Recife, northeastern Brazil.METHODS:HLA DQ2 and DQ8 genotyping was performed for 73 individuals with celiac disease and 126 first-degree relatives with negative transglutaminase serology. The alleles DQA1*05, DQA1*0201, DQB1*02 and DQB1*0302 were identified by sequencing using specific primers and the EU-DQ kit from the Eurospital Laboratory, Trieste, Italy and double-checked by the All Set SPP kit (Dynal).RESULTS:Among the 73 cases, 50 (68.5%) had the genotype DQ2, 13 (17.8%) had DQ8, 5 (6.8%) had DQ2 and DQ8, and 5 did not have any of these genotypes. Among the 5 negative individuals, four had the B1*02 allele and one did not have any of the alleles studied. B1*02 was the most frequent allele in both groups (94% in the patients and 89% in the control relatives).CONCLUSIONS:In this study, celiac disease was associated with the genotypes DQ2 and DQ8. DQ2 predominated, but the distribution of the frequencies was different from what has been found in European populations and was closer to what has been found in the Americas. The high frequencies of the HLA genotypes DQ2 and DQ8 that were found in first-degree relatives would make it difficult to use these HLA genotypes for routine diagnosis of celiac disease in this group.

Presence of DQ2.2 Associated with DQ2.5 Increases the Risk for Celiac Disease

“…Additionally, in our study, when considering the presence of the DQ2.5 variant without association with DQ8, the frequency found in celiac patients was 75.1%, while in previous studies performed in the Southern and Northeastern regions of Brazil was 65.3% [24] and 68.5%, respectively [23]. The presence of DQ8 alone (i.e., without the concomitant presence of DQ2.5) among our celiac patients was 10.5%.…”

“…Previous studies performed in small series of celiac patients revealed that HLA-DQ2.5 and/or DQ8 were present in 93.1% of celiac patients in the Northeastern region of Brazil, where the miscegenation with Africans and Amerindians is more intense [23]. In the Southern region, where Caucasian ancestry predominates, the frequency of 91.1% was found [24].…”

Celiac disease and HLA-DQ genotype: diagnosis of different genetic risk profiles related to the age in Badajoz, southwestern Spain

“…There are several studies that demonstrate that isolated DQB1*02 would confer a predisposition towards triggering CD (15,25,26,30,31,(36)(37)(38)(39), and the presence of isolated DQA1*05 would not (15,22,25). In our study, 1 % of celiac children and 1.4 % of adults presented isolated DQB1*02 compared to healthy controls (11.1 % of cases).…”

Prevalence of Genetic Susceptibility for Celiac Disease in Blood Donors in São Paulo, Brazil

“…Castro-Antunes et al found genetic predisposition in 78.6% of the patients' relatives in the North East region (4) , and a study performed in the Center West region by Martins et al, described the DQ2 allele in 42% of the relatives, being DQ2 associated to DRB1*04 in 13% and DRB1*04 alone in 4.6% of the individuals (19) . However, since the studies were performed in relatives, it was not possible to detect the real genetic predisposition for CD in the Brazilian general population.…”