Mannose-binding lectin (MBL2) gene polymorphism in sickle cell anemia: an Egyptian study

Abstract

Sickle cell disease (SCD) is an inherited disorder of sickle hemoglobin affecting millions of people worldwide. The current study aimed at detecting the prevalence of MBL2 exon-1(codons 52, 54, and 57) and promoter region (-221, X/Y) genetic polymorphisms in Egyptian children with SCD to clear out its possible role as a genetic risk factor for susceptibility to vaso-occlusive crisis (VOC) and/or infections. Genotyping of exon-1 and the promoter region was done by polymerase chain reaction for 50 SCD patients and 50 healthy controls. The frequency of MBL2 promoter polymorphism was 32% for the heteromutant genotype, Y/X and 8% for the homomutant genotype, and X/X with no statistical difference in the distribution of the mutant genotypes between SCD patients and controls. MBL2 exon-1 gene mutation in SCD patients was 18% for the heteromutant genotype A/O and 32% for the homomutant genotype O/O. The O/O genotype was significantly higher in SCD patients. Mutation at codon 57 of exon-1 (C allele) was significantly higher in SCD patients. The frequency of intermediate MBL2 expressers was significantly higher in the control group, while the frequency of low MBL2 expressers was higher among the patients. The distribution of MBL2 expressers did not differ between SCD patients with or without recurrent attacks of VOC. There was no association between MBL2 exon-1 or promoter region (-221 Y/X) genetic polymorphisms and the susceptibility to neither VOC nor infections in Egyptian children with SCD.