Body clock linked to diabetes and high blood sugar in...(vide new options for treating people. ...),Health

In healthy people, blood sugar levels are kept under control by insulin, which the pancreas releases in varying amounts at different periods during a 24-hour natural cycle. The researchers suggest that when there is a genetic abnormality that affects melatonin levels and sleep patterns, this may also disturb the levels of insulin in the blood, preventing the body from maintaining control of blood sugar levels.

Insulin is normally secreted in peaks during the daytime, in order to allow blood sugar from meals to be processed properly, and at lower levels at night. In contrast, melatonin levels are low during the daytime and high at night.

The new study is part of a series of discoveries about the genetics of diabetes made by Professor Froguel and his colleagues. In May 2008 they identified a genetic mutation that can raise the amount of sugar in a person's blood to harmful levels and in February 2007 they identified the key genes associated with a risk of developing type-2 diabetes in the first study to map the genes of any disease in such detail.

The new study shows that identifying which people have high numbers of genetic mutations can reveal who is at most risk of developing high blood sugar levels. On average, the more genetic mutations associated with high blood sugar levels people had, the higher their blood sugar level.

For example, people with five genetic mutations had an average fasting blood sugar level of 5.4, whereas people with one mutation had an average level of 5.12.

Forty three percent of those carrying six or more mutations had levels of fasting blood glucose of 5.6 mmol/l or more. This level is defined as being 'impaired' by the American Diabetes Association, meaning that such people have a very high risk of developing diabetes in the future.

Professor Froguel added: "We have been developing quite a clear picture of the key genes involved wit
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