OBJECTIVE: Henoch Schnlein purpura (HSP) is an autoimmune vasculitis syndrome of unknown etiology. Recently, some research has shown that the polymorphisms of Mannose binding lectin (MBL) gene can decrease the serum MBL level, and MBL deficiency may be associated with increased susceptibility to infection and autoimmune diseases. This study aims at exploring the correlation between MBL codon 54 polymorphism and HSP in Han nationality children. METHODS: One hundred and four children with HSP and 160 healthy controls were enrolled in this study. The genotypes of MBL gene 54 codon were detected by Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR RFLP). RESULTS: The genotype frequency of heterozygote (GGC/GAC) in the HSP group was significantly higher than that in the healthy controls ( 51.9% vs 25.0% ) (P< 0.05 ), whereas that of homozygote (GGC/GGC) in the former was significantly lower than that of the latter (46.2% vs 73.8%) (P< 0.05 ). The allele frequency of GAC was higher in HSP patients than that in controls ( 0.279 vs 0.138 ) (P< 0.05 ), whereas that of GGC in HSP patients was lower than that in controls ( 0.721 vs 0.862 ) (P< 0.05 ). The variant allele (GAC) was markedly associated with onset of HSP (OR= 2.46 , 95% CI= 1.32 - 4.48 ; P< 0.05 ). In addition, in the HSP group more patients carrying the variant allele (GAC) had episodes of upper respiratory or gastrointestinal infections before onset of HSP compared with those with GGC homozygote (P< 0.05 ). CONCLUSIONS: MBL gene condon 54 mutation might be related to the pathogenesis of HSP.