Background: Genetic determinants of susceptibility to severe acute respiratory syndrome coronavirus (SARS-CoV) infection remain unknown. We assessed whether mannose-binding lectin (MBL) gene polymorphisms were associated with susceptibility to SARS-CoV infection or disease severity in an ethnically homogeneous population born in northern China.
Methods: The frequencies of 1 mutation in codon 54 and 3 promoter polymorphisms at nt -550, -221, and 4 were ascertained in 352 patients with SARS and 392 control subjects, by means of polymerase chain reaction direct sequencing.
Results: Of 352 patients with SARS and 392 control subjects, 120 (34.4%) and 91 (23.2%) were carriers of the codon 54 variant, respectively (odds ratio [OR], 1.73 [95% confidence interval {CI}, 1.25-2.39]; P=.00086). A total of 123 (36.0%) of 352 patients with SARS and 100 (25.5%) of 392 control subjects had haplotype pairs associated with medium or low expression of MBL (OR, 1.67 [95% CI, 1.21-2.29]; P=.00187). The population-attributable fraction of patients with SARS that was associated with having the codon 54 variant was 20.1% (95% CI, 7.9%-32.3%).
Conclusions: MBL gene polymorphisms were significantly associated with susceptibility to SARS-CoV infection; this might be explained by the reduced expression of functional MBL secondary to having the codon 54 variant.