Correlation between point mutation frequency of MBL coding gene Exon 1 and MBL plasma concentration in Chinese Hans and Mongolia people

Objective To analyze the point mutation of MBL (mannose-binding lectin or mannan-binding lectin) Exon 1 at codon 54 in healthy Chinese Hans and Mongolia people, to measure the plasma levels of MBL, and to analyze the association between gene mutation frequency and the plasma concentrations of MBL in both groups. Methods Blood samples were from collected 56 healthy Hans and 37 healthy Mongolia people; Establishment of PCR amplification and method for the detection of MBL point mutation (PCR-RFLP); Assay for plasma MBL: MBL plasma concentrations were measured using MBL ELISA. Results (1) No bands were found in non-specificity samples (HAV, HBV, HCV and TB) , and the sequences of PCR products were the same as the expected ones by sequencing analysis. (2) Frequency of point mutation in healthy Hans and Mongolia people were 0.2321 and 0.1757 respectively. (3) The average plasma MBL concentration was 1998.750μg/L, standard deviation was 1505.152 in 57 healthy Hans; that of 37 Mongolia people was 2525.676μg/L, standard deviation was 1955.188. (4) Analysis of correlation between MBL concentrations and gene mutation frequency in healthy Hans: Frequency of point mutation was 1.00 when the MBL concentrations were below 100μg/L; frequency of point mutation was 0.4524 when in the range of 100μg /L to 1000μg /L; frequency of point mutation was 0.0156 when over 1000μg /L. (5) Frequency of point mutation was 1.00 when the MBL concentrations were below 100μg /L; frequency of point mutation was 0.4583 from 100μg /L to 1000μg/L; no point mutation was found in over 1000μg/L. Conclusion (1) PCR-RFLP, detecting the point mutation at codon 54 of MBL coding gene, had a high specificity, reproducibility and good sensitivity. (2) The frequency of mutation at codon 54 of MBL coding gene had been determined in both healthy Hans and Mongolia people, the frequency was higher in healthy Hans than in Mongolia people, but no statistical significant(χ 2=0.8574,P0.05 ). (3) The MBL plasma concentrations were measured in both healthy Hans and Mongolia people, the MBL levels was lower in healthy Hans than in Mongolia people, but there was no statistical significance(t=1.448, 0.1P0.2). (4) There was a negative correlation between frequency of point mutation and MBL concentrations in both Hans and Mongolia people(r=-0.62, r=-0.641, respectively).