Scientists find gene mutation that sheds light on causes of osteoporosis

Medical Research Council scientists based at University of Southampton have made an important genetic discovery that could have significant implications for diagnosing and treating osteoporosis - the disease that results in brittle bones. The findings are published in the October 2004 edition of the Journal of Clinical Endocrinology and Metabolism.

Osteoporosis affects one in three women over the age of fifty. Finding answers to the health problem, which will benefit both patients and the NHS, is a priority. This new research offers an insight into how taking control of nutrition and lifestyle really could be the key to influencing genetic factors that play an important role in our health in later life and in the health of our children.

The team led by Professor Cyrus Cooper has found startling new evidence showing that some people in the population may have a defect in a gene that regulates the amount of growth hormone produced by the body, influencing how well bones develop and grow.

More importantly they have found that the growth hormone (GH1) gene appears to be modulated in part, by environmental factors in early life. The team found that having a genetic makeup with the mutation that might predispose to osteoporosis was a major determining factor in later bone density and risk of fracture only if there was also experience of environmental adversity (for example poor nutrition) in the womb and through infancy.

The MRC team at Southampton has spent many years exploring the influence of maternal body composition and lifestyle on the later risk of osteoporotic fractures in the mothers' children. Their latest work reinforces the idea that the interplay between your genes and what you are exposed to in your environment, both before birth and during infancy, can influence your overall risk of osteoporosis many decades later.

The researchers used a comprehensive set of birth and health records compiled for a group of 300 Hertfordshire men and women who were born during the 1920s and 30s. Many are still living locally, giving researchers a unique insight into the health of a group of people who are also representative of the population as a whole.

Professor Cooper said: "This has altered our understanding of the complex relationship between genes and the early environment. We have known for a long time that genetic and environmental influences contribute to who we are and our health prospects. This is the first time research has shown the extent to which these early environmental factors (such as maternal nutrition, smoking and exercise) impact on the function of genes which have a key role to play in the development of a healthy skeleton.

"Although there is a strong genetic contribution to skeletal growth, our work also suggests that the impact of an adverse genetic make-up might be minimised by improving the environment in the womb. For example, paying attention to maternal nutrition, reducing maternal smoking and avoiding very heavy physical activity by mothers in late pregnancy.

"In addition, fracture risk can be further reduced by changes in lifestyle, such as the optimisation of diet and physical activity during childhood and later adult life. The research challenge ahead is to precisely identify the optimum nutrition and lifestyle for mothers, in order to reduce the risk of fractures in their offspring's generation."