Genetic polymorphisms in the surfactant proteins in systemic sclerosis in Japanese: T/T genotype at 1580 C/T (Thr131Ile) in the SP-B gene reduces the risk of interstitial lung disease.
OBJECTIVE
To investigate the association between single-nucleotide polymorphisms (SNPs) in the pulmonary surfactant protein (SP) genes and the presence or absence of interstitial lung disease (ILD) in SSc patients.


METHODS
We studied 127 Japanese patients with SSc and 206 normal subjects. Investigated SNPs were C/T within amino acid (aa) 219, Arg219Trp in the SP-A1 gene (rs4253527), C/T within aa 131 (at nucleotide 1580) and Thr131Ile of the SP-B gene (rs1130866). Genotypes were determined by the TaqMan method.


RESULTS
Genotype frequencies were not different between the SSc patients and normal controls for both loci. The patients were subsequently divided into two groups based on presence or absence of ILD. In the SNP in the SP-B gene, the frequency of the T/T genotype was significantly lower in the patients with ILD than in those without ILD. Limited in the patients who were positive for anti-Scl-70 antibody, the difference in the frequency of the T/T genotype between the ILD-positive and ILD-negative groups became more apparent. On the other hand, in the SNP in the SP-A1 gene, there was no significant skewing for a certain genotype.


CONCLUSIONS
In SSc, where massive fibrosis occurs, possession of the T/T genotype in the SP-B gene would reduce the risk of ILD in Japanese.
Sumita
Y
Y
Third Department of Internal Medicine, Faculty of Medicine, Shimane University, Shimane, Japan.
Sugiura
T
T
Kawaguchi
Y
Y
Baba
S
S
Soejima
M
M
Murakawa
Y
Y
Hara
M
M
Kamatani
N
N
D000328:Adult; D016022:Case-Control Studies; D016001:Confidence Intervals; D005260:Female; D005786:Gene Expression Regulation; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007564:Japan; D017563:Lung Diseases, Interstitial / Q000235:genetics* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D011336:Probability; D037701:Pulmonary Surfactant-Associated Protein B / Q000235:genetics* / Q000378:metabolism; D012016:Reference Values; D018570:Risk Assessment; D012595:Scleroderma, Systemic / Q000235:genetics* / Q000503:physiopathology; D012680:Sensitivity and Specificity
D037701:Pulmonary Surfactant-Associated Protein B