Disorders of bone remodelling, predominantly osteoporosis, are among the most common public health problems in the Western world. Osteoporosis is a disease characterized by low bone mass and deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk. Prevalence of the disease in women increases with advancing age. In the USA it has been estimated that 30% of postmenopausal white women have osteoporosis and a further 54% have a low bone mass (osteopenia). By age 80 it is estimated that 70% of women are osteoporotic at the hip, lumbar spine or forearm and a further 27% are osteopenic. A high percentage of these experience one or more osteoporosis related fractures, often resulting in the need for long term nursing care. Hip fractures are the most drastic, with a mortality rate of almost 20%.

In addition to human suffering, the financial costs of osteoporosis are considerable. In the USA the total expenditure for osteoporotic related fractures is estimated at US$ 20 billion annually. These include costs for hospital care, long term residential care, loss of work days and pharmacological treatments among many others. It is envisaged that total number of fractures, and hence the cost to the community, will increase over the next 50 years as a result of the increase in the elderly population.

Osteoporosis testing is driven primarily by the need to identify patients at risk for osteoporotic fractures. The diagnosis relies mainly on bone mass measurement. From epidemiological studies it is known that the rate of prevalent fractures increases substantially below a certain level of bone mass. This value is referred to as the fracture threshold, and is generally set at 2 standard deviations below the mean for a young normal population.

The current impact of osteoporosis on health care costs, quality of life and total morbidity and mortality implies an immediate need for more sensitive methods of predicting development of the disease. It is essential to be able to assess the risk of osteoporosis and identify the risk factors that eventually will lead to low bone mass and/or osteoporosis in the population. Unfortunately, information on genetic risk factors associated with or contributing to the development of osteoporosis is limited.

The low bone mass that is common with advancing age results from a combination of suboptimal peak bone mass attained in early adulthood, and increased rates of bone loss that occur after middle age. It is known that peak bone mass is dependent primarily on genetic factors, although it is also influenced by environment factors like calcium intake in the diet and physical activity during childhood and adolescence. The genetic factors explain the variability in peak bone mass within different ethnic groups, for example Blacks have greater peak bone mass than Caucasians, who in turn have a higher bone mass than Asians. The influence of genetic factors on peak bone mass has been confirmed in fair studies over the last 20 years.

Synergene, as part of its internal Research and Development program, is planning to engage in a research project for the localisation of genetic alterations that confer increased predisposition to osteoporosis. We anticipate that the identification these genetic risk factors would be of significant importance in the assessment of risk for developing osteoporosis.