Background: Otosclerosis (OTSC) is among the most common causes of a late-onset hearing loss in adults and is characterized by an abnormal bone growth in the otic capsule. Alteration in the osteoprotegerin (OPG) expression has been suggested in the implication of OTSC pathogenesis.
Methods: A case-control association study of rs2228568, rs7844539, rs3102734 and rs2073618 single nucleotide polymorphisms (SNPs) in the OPG gene was performed in a Tunisian-North African population composed of 183 unrelated OTSC patients and 177 healthy subjects. In addition, a multilocus association and a meta-analysis of existing studies were conducted.
Results: Rs3102734 (p = 0.013) and rs2073618 (p = 0.007) were significantly associated with OTSC, which were predominantly detected in females after multiple corrections. Among the OPG studied SNPs, the haplotypes A-A-C-G (p = 0.0001) and A-A-C-C (p = 0.0004) were significantly associated with OTSC in females. Multilocus association revealed that the SNPs: rs2073618 in OPG, rs1800472 in TGFβ1, rs39335, rs39350 and rs39374 in RELN, and rs494252 in chromosome 11 showed significant OTSC-associated alleles in Tunisian individuals. In addition, meta-analysis of the rs2073618 SNP in Tunisian, Indian and Italian populations revealed evidence of an association with OTSC (OR of 0.826, 95% CI [0.691-0.987], p = 0.035).
Conclusions: Our findings suggest that rs3102734 and rs2073618 variants are associated with OTSC in North African ethnic Tunisian population. Meta-analysis of the rs2073618 in three different ethnic population groups indicated an association with OTSC.
Keywords: Case-control association; Meta-analysis; Multilocus association; OPG; Otosclerosis; Polymorphisms.