Mutational Study in the Exon2 of Osteoprotegrin Gene in Osteoporotic Women in Chahar Mahal va Bakhtiari Province of Iran

Background: Osteoporosis is a multifactorial disease. Mutation in cystein-rich domain2 (CRD2) and cystein-rich domain3 (CRD3) of osteoprotegrin protein can prevent its interaction with receptor activator of nuclear factor kappa beta (RANKL) ligand and lead to osteoporosis. Objectives: This study aimed to investigate the possible alteration in exon2 of the osteoprotegrin gene encoding CRD2 and CRD3 domains in osteoporotic women in Chahar Mahal va Bakhtiari Province of Iran. Methods: The N-terminal region of human osteoprotegerin (OPG) protein was aligned with mice osteoprotegrin proteins using Clustal Omega multiple alignment tool. The genomic DNA of 72 osteoporotic women was extracted by commercial kit. The region of exon2 of the OPG gene encoding CRD2 and CRD3 was amplified by PCR and sequenced by DNA sequencing. Results: The result of multiple protein alignment showed dissimilarities among three species in terms of CRD2 and CRD3 domains. The results of polymerase chain reaction (PCR) amplification and DNA sequencing indicated that CRD2 and CRD3 sequence were intact in osteoporotic women. Conclusion: Due to the binding possibility of OPG protein with RANKL ligand, it was concluded that the expression of OPG gene may have been different in osteoporotic women. However, it was recommended that further studies should be conducted in order to confirm this finding.