Polymorphisms in the Mannose Binding Lectin (MBL) Gene Are Not Associated with Radiographic Erosions in Rheumatoid or Inflammatory Polyarthritis

Objective. To investigate the association between the mannose binding lectin gene (MBL) promoter and structural single nucleotide polymorphisms (SNP) with development of erosions in a primary care inception cohort of patients with inflammatory polyarthritis (IP). Methods. DNA was available from 438 patients with IP and radiographic data were available for all patients at 5 years. Four SNP [MBL-550*C/G (H/L), MBL-221*G/C (Y/X), MBL codon 52*C/T, and MBL codon 54*G/A] mapping to the MBL gene were genotyped using primer extension techniques. Allele frequencies were compared between IP cases with erosions by 5 years and those without. Results. None of the SNP were associated with erosive outcomes by 5 years. Furthermore there was no association with Larsen score by 1 or 5 years or with the change in Larsen score between 1 and 5 years. Similarly, the genotype combinations known to encode for low MBL protein production were not associated with erosive outcome in the IP cohort as a whole or in those with rheumatoid arthritis (RA) by 5 years. Conclusion. Polymorphism within the MBL gene is not associated with presence or extent of erosions by 5 years in patients with RA or IP.