The role of major histocompatibility complex alleles in the susceptibility of Brazilian patients to develop the myogenic type of Graves' orbitopathy.
OBJECTIVE
To assess the frequency of the genetic markers HLA-DRB1 and DQB1 in patients with Graves' orbitopathy (GO) with and without extraocular muscle involvement.


METHODS
The frequencies of class II HLA-DRB1 and DQB1 allele groups were determined for 81 Brazilian patients with GO and 161 normal subjects. The patients were divided into myogenic and nonmyogenic groups based on the clinical characteristics of the orbitopathy and quantitative computed tomography analysis of the extraocular muscle (EOM) dimensions.


RESULTS
Compared to the frequency obtained for samples of normal subjects of the Brazilian population, HLA-DRB1 16 ( pc=0.008) was overrepresented in myogenic and HLA-DRB1 03 ( pc=0.02) in nonmyogenic patients.


CONCLUSIONS
The association between the HLA-DRB1 16 and the myogenic subtype of GO suggests that EOM involvement in GO may be genetically predisposed.
Akaishi
Patricia Mitiko Santello
PM
Department of Ophthalmology, Otorhinolaryngology, and Head and Neck Surgery, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirao Preto, Sao Paulo, Brazil. patriciamitiko@gmail.com
Cruz
Antonio Augusto Velasco
AA
Silva
Fabricio Leon Mascaro
FL
Rodrigues
Maria de Lourdes Veronesi
Mde L
Maciel
Lea Maria Zanini
LM
Donadi
Eduardo Antonio
EA
D000328:Adult; D000483:Alleles; D001938:Brazil; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006111:Graves Disease / Q000175:diagnosis* / Q000235:genetics* / Q000276:immunology; D006683:HLA-DQ Antigens / Q000235:genetics*; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006801:Humans; D008285:Major Histocompatibility Complex / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009135:Muscular Diseases / Q000150:complications / Q000235:genetics
D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains