Multiple sclerosis: New study holds clues about causes

A big international study that has led scientists to identify the major common genetic variants that contribute to the cause of the devastating neurologic disease multiple sclerosis (MS) was published today in the scientific journal Nature.
More than a thousand New Zealanders and University of Otago researchers contributed to what was one of the largest human genetic studies ever undertaken.
The study represents years of work by the International Multiple Sclerosis Genetics Consortium (IMSGC) involving more than 250 researchers in 15 countries.
University of Otago, Christchurch, researchers were involved in the study and more than 1000 New Zealanders contributed samples. MS is a disorder of the central nervous system which includes the brain, spinal cord and optic nerves.
The study confirmed the presence of up to 57 MS genes with a pattern that showed the reason some people got MS and others did not was largely due to subtle, inherited differences in immune function. It pointed to a pivotal role for T cells -- the "orchestra leaders" of the immune system -- and made it clear that MS was primarily an immunologic disease.
The New Zealand contribution was led by Professor Bruce Taylor, now based in Tasmania, and Dr Deborah Mason, a clinical senior lecturer at the University of Otago, Christchurch, and consultant neurologist at Canterbury District Health Board.
In 2006 Drs Taylor and Mason and colleagues from the University of Otago, and the University of Canterbury, conducted the first ever national prevalence study of MS.
As part of an ongoing collaboration with other MS researchers the Australia and New Zealand Multiple Sclerosis Genetics Consortium (ANZgene) was formed in 2007, Dr Mason said.
ANZgene researchers identified two new genetic areas or loci which conferred susceptibility to MS. This study was published in Nature Genetics in 2009 and led to its involvement with the Wellcome Trust Case Control Consortium and The International Multiple Sclerosis Genetics Consortium.
Dr Mason said one of the continuing controversies in MS was whether damage to the nervous system was primarily a degenerative process or whether it resulted from inflammation mediated by the immune system. The study published today in Nature strongly supports the latter premise and confirms a pivotal role of the immune system.
"Whilst we still do not understand what causes or triggers the immune dysfunction, widely believed to be an environmental trigger, this study increases our understanding of the immune mechanisms which contribute to damage," Dr Mason said.
"In addition the study also confirms a possible link between MS and a proposed environmental factor, Vitamin D metabolism."
The Australian contribution was led by Professor Graeme Stewart, a clinical immunologist in the Westmead Millennium Institute, University of Sydney.
"Discovering so many new leads is an enormous step towards understanding the cause of MS," Prof Stewart said.
"Most importantly, for people with MS, these genes also strengthen the case for immunologic treatments currently in clinical trials and point to new therapeutic approaches."
- NZPA