title: BTNL2 gene polymorphism associations with susceptibility and phenotype expression in sarcoidosis.
abstract: A functional polymorphism within butyrophilin-like 2 (BTNL2) gene has been described as a potential risk factor for sarcoidosis. The association between chronicity and the rs2076530 SNP A allele has also been reported. This study evaluates the BTNL2 rs2076530 G/A allele associations with sarcoidosis susceptibility and disease evolution in a Portuguese cohort of patients. A case-control study of 151 patients and 150 controls was performed. Allele frequencies were compared with Chi-square test in a univariate analysis and with logistic regression in a multivariate analysis. BTNL2 rs206530 A allele frequencies were significantly higher in sarcoidosis with no linkage disequilibrium with HLA-DRB1 alleles, except in the subgroup of patients with Löfgren syndrome where the determinant allele was HLA-DRB1*03. The A allele was also increased in those with isolated thoracic disease, with no differences regarding radiological stages or disease evolution. HLA-DRB1*03, besides the association with Löfgren syndrome was significantly related with disease resolution. Our data confirms the association of BTNL2 rs2076530 A allele with sarcoidosis susceptibility in a Portuguese population. We found independent genetic risk factors in clinically distinct disease phenotypes: BTNL2 rs2076530 A allele in patients without Löfgren syndrome or with isolated thoracic disease, and HLA-DRB1*03 in Löfgren syndrome or disease resolution.
authors.affiliation: Pneumology Department, Centro Hospitalar São João, Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal. amorais3@hotmail.com
authors.forename: António
authors.initials: A
authors.lastname: Morais
authors.forename: Bruno
authors.initials: B
authors.lastname: Lima
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Peixoto
authors.forename: Helena
authors.initials: H
authors.lastname: Alves
authors.forename: Agostinho
authors.initials: A
authors.lastname: Marques
authors.forename: Luís
authors.initials: L
authors.lastname: Delgado
mesh_terms: D000328:Adult; D000071797:Butyrophilins; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D059811:HLA-DRB1 Chains / Q000235:genetics; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011174:Portugal / Q000208:ethnology; D012307:Risk Factors; D017565:Sarcoidosis, Pulmonary / Q000235:genetics*
chemical_list: C408263:BTNL2 protein, human; D000071797:Butyrophilins; D059811:HLA-DRB1 Chains; D008562:Membrane Glycoproteins