Friday, June 17, 2016

Multiple Sclerosis


Multiple Sclerosis (MS) is a disease that affects a number of my friends in various degrees.  It’s a demyelinating disease in which the insulating cover, known as the myelin sheath, of nerve cells in the brain and spinal cord are damaged.  The result as you can imagine can be very debilitating and can lead to death.  While it is not my field of study, I’m always on the lookout for articles regarding this disease.  Interestingly enough I came across two separate articles on the same day regarding the disease that on face value seem unrelated, but actually fit together.

The first article was in IFLScience by Graham Wright referencing a report in the The Conversation describing a mystery in MS rates of Multiple Sclerosis in Northern Scotland.  MS has been shown to be very prevalent on the Orkney isles, which lie off the northernmost mainland.  In these reports, studies supported the theory that low levels of vitamin D were a key initiating factor in the damage to neuronal transmission pathways.  The thinking is that because these islands are so far north access to sunlight is limited, resulting in less active vitamin D being produced.  The mystery is that while MS in Orkney is 402 cases per 100,000, compared to 200 in the rest of Scotland and 165 in England, the even more northerly Shetland isles have a rate of 295 per 100,000.  This indicates that more is going on than just sunlight exposure, with speculation as to a cultural shift between the two island groups and sun exposure.


Simplified Pedigree for Families Presenting the NR1H3 p.Arg415Gln Mutation

Figure 1. Simplified Pedigree for Families Presenting the NR1H3 p.Arg415Gln Mutation.  Two family trees that had the MS-causing mutation. “M” denotes individuals with the mutation, with black circles indicating individuals with MS.  Image courtesy of the University of British Columbia
The second was an article in Lab Manager reporting on a research paper in the journal Neuron describing the genetic cause of multiple sclerosis in two different families in Canada.  These families each had several diagnosed with the disease with a rapid progressive type.  The mutation found was actually a substitution of a single nucleic acid in the gene called NR1H3, which produces a protein known as LXRA.  This protein acts as an on/off switch for other genes that prevent excessive inflammation.

Like the Orkney isles, Canada has one of the highest rates of MS in the world, with an estimated 100,000 Canadians living with MS (286 cases per 100,000).  The obvious connection between the two groups is that the Scots are among the first Europeans to establish themselves in Canada and are the third largest ethnic group in the country. In the 2011 National Household Survey, a total of 4,714,970 Canadians, or 14.1 per cent of the population, listed themselves as being of Scottish origin. 

While these findings do not identify the root cause for all MS cases it does provide information on new research pathways, as well as provide information regarding new animal models.  Genetic screening might also provide information for earlier intervention (such as vitamin D supplementation) and more aggressive treatments for those identified as having the mutation.  I like to think that instrumentation provided by the company I work for, BioTek Instruments, can help with this research.

References
  1. Weiss, E. ,L. Zgaga,S. Read, S. Wild, M. G. Dunlop, H. Campbell, R. McQuillan, and J. F. Wilson  (2016) Farming, Foreign Holidays, and Viatmin D in Orkney, PLOS one, http://dx.doi.org/10.1371/journal.pone.0155633
  2. Zhe Wang, Z.,  A. D> Sadovnick, A. L. Traboulsee, J. P. Ross, C. Q. Bernales, M. Encarnacion, I. M. Yee,M. de Lemos, T. Greenwood, J. D. Lee, G. Wright, C. J. Ross, S. Zhang, W. Song, and  C. Vilariño-Güell (2016) Nuclear Receptor NR1H3 in Familial Multiple Sclerosis, Neuron, 90(5):948-954. DOI: http://dx.doi.org/10.1016/j.neuron.2016.04.039

By: BioTek Instruments, Paul Held, PhD., Laboratory Manager

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