Objective: To investigate the relationship between mannose-binding lectin (MBL) gene exon 1 site mutations and chronic rheumatic heart disease (CRHD).
Methods: Polymerase chain reaction (PCR) and restrictive fragment length Polymorphism (RFLP) were used to investigate the MBL exon 1 alleles in 36 patients with CRHD and 39 normal people.
Results: No C and D alleles of MBL gene were found in both groups. Eleven patients had A/B alleles, 1 patient had B/B alleles, 15 normal people had A/B alleles but none of the 39 normal people had B/B alleles. Statistic analyses showed no significant difference between CRHD group and normal group. But when the age of heart-disease-symptom-onset (HDSO) of the CRHD group were considered, we found that the mean HDSO age of patients with B allele was 30 +/- 14 years and the mean HDSO age of patients with AA homozygous was 37 +/- 11 years. P < 0.05.
Conclusion: MBL gene mutations may not be a main factor of the pathogenesis of CRHD, but MBL deficiency may facilitate the development of CRHD in younger people and accelerate the progress of CRHD. This is consistent with the phenomenon that the most susceptible people of rheumatic heart disease are teenagers.