Thursday 11 August 2011 10:34am
In one of the largest human genetic studies ever undertaken, scientists have identified the major common genetic variants that contribute to the cause of the devastating neurologic disease, multiple sclerosis (MS).
The results of the study are published today in the prestigious scientific journal, Nature. They represent 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.
The study confirmed the presence of up to 57 MS genes with a remarkable pattern that shows that the reason some people get MS and others don’t is largely due to subtle, inherited differences in immune function. It points to a pivotal role for T cells – the ‘orchestra leaders’ of the immune system and makes it clear that MS is 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, Mason and colleagues from the University of Otago, and the University of Canterbury, conducted the first ever national prevalence study of MS.
Dr Mason says in 2007, as part of an ongoing collaboration with other MS researchers the Australia and New Zealand Multiple Sclerosis Genetics Consortium (ANZgene) was formed.
ANZgene researchers identified two new genetic areas or loci which conferred susceptibility to MS. This study was published in Nature Genetics in 2009 (2) and lead to its involvement with the Wellcome Trust Case Control Consortium and The International Multiple Sclerosis Genetics Consortium (IMSGC).
Dr Mason says one of the ongoing controversies in MS is whether damage to the nervous system is primarily a degenerative process or whether it results from inflammation mediated by the immune system. The study published today in Nature strongly supports the later 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. In addition the study also confirms a possible link between MS and a proposed environmental factor, Vitamin D metabolism,’’ Dr Mason says.
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,” Professor Stewart says. “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.”
For further information, contact
Dr Deborah Mason
Mob 64 21 400 893
Note: Dr Mason has pre-arranged clinics all day Thursday.
Senior Communications Advisor
University of Otago, Christchurch
Mob 64 27 222 6016
About multiple sclerosis (MS)
Multiple sclerosis is one of the most common neurological conditions among young adults, affecting around 20,000 Australians and 2.5 million individuals worldwide. It is most commonly diagnosed between the ages of 20 and 40, and 75% of those diagnosed are women. The disease results from damage to nerve fibres and their protective insulation, the myelin sheath, in the brain and spinal cord. The affected pathways - responsible in health for everyday activities such as seeing, walking, feeling, thinking and controlling the bowel and bladder – are prevented from 'firing' properly and eventually are destroyed.
The findings announced today focus attention on the pivotal role of the immune system in causing the damage and help to explain the nature of the immune attack on the brain and spinal cord.
The path to discovery of the “MS genes”
The first MS gene, HLA was discovered in 1972. It took until 2007 to confirm the second MS gene, Interleukin 7 receptor (IL7R) following work by Prof Stewart’s team at the Westmead Millennium Institute and at the Karolinska Institute, Stockholm.
In 2009 the ANZgene consortium reported 2 new MS genes, a Vitamin D pathway gene and CD40.
The rapid rise to 57 confirmed MS genes in 2011 results from remarkable advances in science over the past 10 years : (i) knowledge of the human genome (ii) extraordinary automated technologies allowing rapid genetic typing of thousands of DNA samples (iii) plummeting costs/test (iv) computer capacity to handle the statistical analyses and (v) national and international consortia amassing large DNA banks. These have allowed whole genome screening of thousands of patients compared to healthy controls.
The IMSGC whole genome screen involved over 27,000 people: 9,772 MS patients and 17,376 healthy controls.
The study is reminiscent of Winston Churchill’s letter to President Roosevelt in Feb 1941 when he wrote “…give us the tools and we will finish the job”
There are likely to be other rare genetic variants yet to discovered using new technologies but the remarkable pattern of immune system genes reported in the Nature paper will remain as will the insights it brings to understanding the cause of MS.
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