Single-nucleotide polymorphisms in CCL2 gene are not associated with susceptibility to systemic sclerosis

Objective. To validate the reported association between CC chemokine ligand 2 (CCL2) –2518 G single nucleotide polymorphism and systemic sclerosis (SSc) in a much larger cohort of patients. We also performed subgroup analysis to test the hypothesis that CCL2 variants predispose to specific disease phenotypes. Methods. Ninety-four Caucasian patients with SSc and 102 matched controls were genotyped by sequence-specific primers-polymerase chain reaction (SSP-PCR) methodology. Results. Six biallelic single-nucleotide polymorphisms (SNP) were investigated (3 in the promoter region, 2 in the exon-coding sequence, and 1 in the 3 untranslated region), in addition to the known functional –2518 (A/G) variant. Six major haplotypes were constructed across all 7 SNP positions. No significant differences in genotype, allele, or haplotype frequency were observed between patients and controls or within disease subgroups. Conclusion. Genetic polymorphisms within CCL2 gene are associated with susceptibility neither to SSc nor to specific disease phenotypes.