Introduction:
RANKL is a key cytokine involved in osteoclast differentiation from its precursors, activation and survival of osteoclasts themselves. Because RANKL binds with RANK, the presence of RANK on target cells is a necessary condition of target cell control mediated by RANKL.

Materials and methods:
The study was conducted on a group of 570 women at postmenopausal age (404) and reproductive age (166). The group at postmenopausal age included women with osteoporosis, osteopenia and healthy individuals. Women at reproductive age were healthy. Polymorphism incidence of the examined gene in a group of patients with determined bone mineral density (BMD) and in the control group was studied. The study was performed by means of RFLP-PCR method.

Results:
The obtained results did not show correlation of RANKL gene C-643T polymorphism with decreased bone density and increased risk of osteoporotic changes after menopause.

Conclusions:
Homozygote of TT polymorphism of RANKL receptor gene seems to be an increased risk factor of osteoporosis development and is associated with growth and birth mass.