Association of MBL2 gene polymorphisms with type 2 diabetes and its complications in Moroccan population

The MBL2 gene encodes the mannose-binding lectin protein (MBL), which is secreted by the liver. Several variants of MBL2 have been found to be associated with altered serum levels and susceptibility to various chronic diseases. Defects in MBL protein polymerization that result in functional impairments and/or low serum levels may influence genetic susceptibility to type 2 diabetes (T2D) and its complications. Therefore, the present case-control study was conducted to assess the potential association of six MBL2 gene variants and haplotypes with susceptibility to T2D and its complications in Morocco. The MBL2 gene was genotyped by PCR-sequencing for the promoting, non-coding, and coding regions in 435 individuals. Our findings revealed a significant association between the heterozygous CG and homozygous recessive GG genotypes of the variant at position -221 C > G in the MBL2 gene promoter with an increased risk of T2D. Similarly, for +4 C > T in the non-coding region, statistical analysis indicates a strong association with T2D risk, particularly with the heterozygous CT and homozygous recessive TT genotypes. The LYQC haplotype is also found to be associated with T2D risk. Furthermore, the heterozygous CT genotype, and recessive T allele of the variant at position +4 C > T, and heterozygous GA genotype of codon Gly54Asp of the MBL2 gene, are associated with protection against hypertension in T2D patients. However, no association was observed between MBL2 variants and dyslipidemia in T2D patients. The study concludes that -221 C > G and +4 C > T variants of the MBL2 gene significantly contribute to T2D susceptibility in Morocco.