title: Serologic screening and genetic testing among brazilian patients with celiac disease and their first degree relatives.
abstract: BACKGROUND
  Celiac disease susceptibility has been shown to be associated with the HLA alleles DQA1*0501 and DQB1*0201 (together encoding the DQ2 heterodimer) that are present in practically all celiac disease patients. The DQ8 heterodimer (coded by DQA1*03-DQB1*0302), which is carried on a DRB1*04 (DR4) haplotype, is commonly encoded for by the few celiacs who do not carry the DQ2 heterodimer. Only a few celiac disease patients have been reported without these known risk alleles.
  
  
  OBJECTIVE
  To assess the prevalence of celiac disease in a group of first degree relatives of celiac patients, and the frequency of HLA predisposing alleles both in the group of celiac patients and in their first degree relatives, identifying those first degree relatives who would need further screening for celiac disease.
  
  
  METHODS
  Ninety celiac disease patients and 207 first degree relatives underwent serologic screening for celiac disease (endomysial and transglutaminase antibodies) followed by intestinal biopsy in positive patients. The HLA-DQA1*0501, DQB1*0201 and DRB1*04 frequencies of celiac patients and their first degree relatives were determined utilizing the PCR method.
  
  
  RESULTS
  All the celiac disease patients (n = 90) with the exception of one (1.1%) carried at least one of the alleles investigated. Altogether 11 (5.3%) of the investigated first degree relatives did not carry any of the alleles studied. Fourteen (6.7%) new cases of celiac disease were found among the 207 celiac disease patients first degree relatives.
  
  
  CONCLUSIONS
  Considering the cost-benefit of the HLA typing of all the first degree relatives of celiac patients, their HLA status should be decided on an individual basis, taking account of their profile and preferences, and the existence of other medical conditions.
authors.affiliation: University of Brasilia, DF, Brazil.
authors.forename: Rita de Cássia Azevedo
authors.initials: Rde C
authors.lastname: Martins
authors.forename: Lenora
authors.initials: L
authors.lastname: Gandolfi
authors.forename: Inês Cristina
authors.initials: IC
authors.lastname: Modelli
authors.forename: Rodrigo Coutinho de
authors.initials: RC
authors.lastname: Almeida
authors.forename: Luiz Claudio
authors.initials: LC
authors.lastname: Castro
authors.forename: Riccardo
authors.initials: R
authors.lastname: Pratesi
mesh_terms: D000293:Adolescent; D000328:Adult; D001938:Brazil / Q000453:epidemiology; D002446:Celiac Disease / Q000453:epidemiology / Q000235:genetics* / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005192:Family Health; D005260:Female; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D006801:Humans; D007223:Infant; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D015995:Prevalence; D055815:Young Adult