Genetic clue to MS identified

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OXFORD, England, Dec. 8 (UPI) -- A rare genetic variant which causes reduced levels of vitamin D appears to be directly linked to multiple sclerosis, British and Canadian researchers say.

Oxford University researchers along with Canadian colleagues at the University of Ottawa, University of British Columbia and McGill University identified the mutated gene in parents of 35 children with MS and in each case the child had inherited the gene, the BBC reported Thursday.

Although the exact cause of MS, an inflammatory disease of the brain and spinal cord, is not yet known, both genetic and environmental factors are known to be involved, medical researchers say.

Just one copy of the mutated gene from either parent affects a key enzyme that leads to lower levels of vitamin D.

The researchers looked for the gene variant in more than 3,000 families of unaffected parents with a child with MS, and found 35 parents who carried one copy of this variant along with one normal copy.

In every one of these 35 cases, their child with MS had inherited the mutated version of the gene, they said.

"All 35 children inheriting the variant is like flipping a coin 35 times and getting 35 heads, entailing odds of 32 billion to one against," George Ebers, lead study author at Oxford University, said.

The research strengthened the case for vitamin D being one potential contributory cause of MS.

"Current opinion suggests that a combination of genetic predisposition, environmental factors such as exposure to sunlight and possibly some sort of trigger, such as a viral infection, interact in some way to start the development of MS," Paul Comer of the charity MS Trust said.