TNFSF13B and rickets: The aim was to determine the existence of a possible association between the serum levels of 25-OH-vitamin D and the serum levels of BAFF in the two groups studied, but despite the fact that the serum levels of BAFF were significantly higher in patients with GD and hypovitaminosis D was more pronounced, no statistically significant correlation was identified between BAFF and vitamin D serum levels across the study groups.