Celiac Disease in Brazilian First-degree Relatives: The Odds Are Five Times Greater for HLA DQ2 Homozygous.

First-degree relatives (FDRs) of 47 outpatients with celiac disease (CD) answered a questionnaire about symptoms related to CD and were investigated for human leukocyte antigen (HLA)-DQ2, DQB102 homozygosis, and DQ8 alleles. Genetically susceptible individuals were tested for antitransglutaminase antibody immunoglobulin A. Seropositive FDR underwent small bowel biopsies.From 114 FDR, 74.5% (n = 85) were positive for DQ2, DQ8, or both haplotypes. Homozygosity of DQB102 was found in 11.4% (n = 13) individuals. Three FDR were previously diagnosed with CD. Among the genetically susceptible individuals, 67.1% had at least 1 symptom related to CD. Seropositivity was 8/82 (9.8%), and 4/8 biopsies were compatible with CD. Therefore, the total number of FDR with CD was 6.1% (7/114), 95% confidence interval (1.71, 10.49). Three out of 7 FDR with CD were HLA DQB102 homozygous. The odds of being CD is 5 times, 95% confidence interval (0.99, 26.23), greater for HLA DQ B102 homozygous in FDR.