A new UK study suggests that a rare genetic variant causing reduced levels of vitamin D may be directly linked to multiple sclerosis.
In order to look for rare genetic changes that could explain a strong clustering of multiple sclerosis (MS) cases in some families, researchers sequenced all the gene-coding regions in the genomes of 43 individuals selected from families in which four or more members had MS (1). They compared the DNA changes they found to DNA records in existing databases, and identified the change in one gene as being important. The analysis showed that when people inherit two copies of this gene they develop a genetic form of rickets – a disease caused by vitamin D deficiency. Just one copy of the mutated gene affects a key enzyme which causes people with it to have lower levels of vitamin D.
The researchers commented that this type of finding has never been seen in any complex disease before. It would be new evidence adding to previous observational studies that have suggested that the level of sunshine the body needs to generate vitamin D is linked to MS. This would be particularly important in Scotland and the rest of the UK, where sunshine levels are low for large portions of the year. Scotland has the greatest incidence of multiple sclerosis of any country in the world. Now there would be enough evidence to carry out large-scale studies of vitamin D supplements for preventing multiple sclerosis, the scientists said.