Background and objective: Chronic obstructive pulmonary disease (COPD) is influenced by multiple genetic and environmental factors. The role of genetic susceptibility in the pathogenesis of COPD has recently gained more attention. The surface lung surfactant protein B plays an important role in COPD pathogenesis. Microsatellite DNA has been characterized in the surfactant protein B alleles D2S388-5 and D2S2232. The aim of this research was to investigate the distribution of the D2S388-5 and D2S2232 microsatellite polymorphisms in smokers of the Kazakh ethnic group in Xinjiang, China, with and without COPD to assess whether such polymorphisms are associated with COPD susceptibility.
Methods: DNA was extracted from the blood of 197 smokers with COPD and 236 control smokers of Kazakh ethnicity. The smokers diagnosed with COPD were registered at the Department of Respiratory Medicine from four different hospitals. The control group was recruited at the medical examination centre from the same area. The polymorphisms of the D2S388-5 and D2S2232 microsatellite loci were measured by multiple short tandem repeat amplification using fluorescence-labelled polymerase chain reaction and capillary electrophoresis.
Results: Nine alleles and 32 genotypes were identified in D2S388-5, while 9 alleles and 31 genotypes were identified in D2S2232. Both genotype distributions in control smokers were in accordance with Hardy–Weinberg equilibrium. The frequency of the 254 bp allele from the D2S388-5 locus was significantly higher in the COPD group versus the control (P < 0.001, odds ratio = 5.942).
Conclusions: D2S388-5 microsatellite polymorphism may be associated with susceptibility to COPD in Xinjiang Kazakhs.