ABSTRACT
Osteoporosis is a widespread disease affecting more than 1/4th of the female and 1/10th of the male population. It is characterised by a low bone mass, which in turn leads to osteoporotic fractures. Bone mass can be described as bone mineral density (BMD). BMD in human population is subject to quite significant interpersonal variability, for 75 to 80% of which, the genetic factors are responsible. To investigate the dependence of BMD on genetic factors, a possible links between the BMD and the natural polymorphism of so called "candidate genes" are checked. The first candidate gene to be investigated was the gene coding for the receptor of the active form of vitamin D. A statistical linkage between the naturally occurring polymorphism of that gene and the BMD was found by many research centres. It was found that certain polymorphic variants of that gene are linked to higher BMD's than the other ones. This trend existed in different human races and various age groups in many countries including Poland. A batch of negative results which appeared in some papers can be explained either by high calcium consumption in the given population, or the existence of another gene affecting bone metabolism and closely coupled to the vitamin D receptor gene. Other investigated and promising genes are the genes coding for other receptors (e.g. oestrogen), regulatory proteins (e.g. IL-6) and structural proteins (e.g. type I collagen).