MUC 5 B promoter polymorphism in J apanese patients with idiopathic pulmonary fibrosis

Background and objective A single nucleotide polymorphism ( SNP ) rs35705950 in the promoter of M ucin 5 B ( MUC 5 B ) has been reported to be associated with idiopathic pulmonary fibrosis ( IPF ) mainly in C aucasian populations. This study was conducted to confirm the association between rs35705950 and IPF in a Japanese population. Methods Genomic DNA was extracted from blood samples in 384 J apanese and 137 G erman subjects, and rs35705950 was detected by commercially available genotyping assay. Results The genotype distributions of rs35705950 in Japanese patients with IPF , nonspecific interstitial pneumonia ( NSIP ) and healthy subjects ( HS ) were significantly different from those in the G erman counterparts ( P  < 0.001, P  < 0.001 and P  = 0.010, respectively). The rs35705950 T allele frequencies in patients with IPF , NSIP and HS were 3.4%, 1.7% and 0.8%, respectively in the Japanese, while they were 33.1%, 27.4% and 4.3%, respectively in the G erman cohort. The T allele frequencies in patients with IPF were significantly higher than those in HS both in the J apanese ( P  = 0.031) and G erman ( P  < 0.001) cohorts. Conclusions The association between rs35705950 and IPF was also present in this J apanese cohort, but was not as strong as the G erman counterpart. To our knowledge, this is the first study to successfully validate the association between rs35705950 and IPF in a J apanese ethnicity.