The presence of the single nucleotide polymorphisms in exon 1 of themannose-binding lectin 2 (MBL2) gene wasevaluated in a sample of 159 patients undergoing coronary artery bypass surgery (71patients undergoing valve replacement surgery and 300 control subjects) toinvestigate a possible association between polymorphisms and heart disease withChlamydia infection. The gene discussed is MBL2; the disease is infection.