Sunshine may help keep MS risk gene at bay

Researchers from the UK and Canada have discovered a gene which increases the risk of Multiple Sclerosis (MS) in people deficient in vitamin D - the so-called 'sunshine vitamin'. The study, published in the journal PLoS Genetics, may help to explain why MS is more common in countries which receive less sunshine.

MS, which affects about 1 in 1000 people worldwide, is an autoimmune disease in which the immune system attacks the central nervous system, destroying the myelin sheath - the fatty coating which surrounds nerve cells and is essential for nerve cell signalling. It is a progressive disease with no cure and usually onsets during adulthood. Previous studies have shown that MS is more common in countries lacking in sunshine, which stimulates vitamin D production in the body, but this is the first time that the disease has been linked to a gene-environment interaction - the study of which is known as 'epigenetics'.

The researchers found that vitamin D stimulates the production of a protein, which in turn activates a gene variant known as DRB1*1501 by binding to an adjacent DNA sequence. Without the production of vitamin D, the gene variant doesn't function properly, increasing the risk of developing MS in adulthood. It is thought that one in 300 people have one copy of the gene variant and one in 100 have two copies.

Government ministers are being urged to consider producing guidelines to encourage pregnant women and young children to take vitamin D supplements, particularly if they are living in countries lacking in sunshine.

'Epigenetics will have important implications, not only for MS, but for other common diseases,' study leader Professor George Ebers, from the Wellcome Trust Centre for Human Genetics at Oxford, told the Guardian. 'For mothers, taking care of their health during their reproductive years may have beneficial effects on the health of their future children or even grandchildren', he added.