Sunday, 16 September 2012

Test for MS. Lay genetics-Does it confuse?

Lin R, Charlesworth J, van der Mei I, Taylor BV. The genetics of multiple sclerosis.  Pract Neurol. 2012 Oct;12(5):279-88.
 

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Improved prevention and treatment will depend on a greater understanding of the causes and mechanisms involved in its onset and progression. MS is clearly driven by both environmental and genetic factors. Established contributory environmental factors include lower ultraviolet radiation exposure and lower vitamin D levels, Epstein-Barr virus and smoking. Our current understanding of MS genetics is undergoing a major upgrade as new genetic technologies are applied to large MS studies. In this article, we review the current literature describing a genetic contribution to MS susceptibility and review the methods to detect genetic variants that may underlie the genetic contribution to MS. We also consider how reporting of genetic discoveries in MS in the lay press has caused some confusion among patients and their families, who, not surprisingly, think that these discoveries can be translated into an available genetic test to diagnose MS or recognise family members at risk of developing MS. We review the current limited clinical use of genetics in the diagnosis and management of MS.


Does the lay press cause confusion? and Do you think these discoveries can lead to genetic test to diagnose MS or recognise family members at risk of developing MS?

MS is likely caused by a complex interaction between multiple genes and environmental factors, leading to inflammatory-mediated central nervous system deterioration. A series of genomic studies have confirmed a central role for the immune system in the development of MS.

Genetic association studies that have now dramatically expanded the roster of MS susceptibility genes beyond the longstanding human leucocyte antigen (HLA) association in MS first identified nearly 40 years ago. More than 50 non-HLA genetic risk factors associated with MS. However, a large proportion of the disease heritability is still unaccounted for. 

So loads more to do. I know what some of you think?

Knowledge is Power and
You do not know where the next big break will come from 

All genes variants do, is increase risk. THERE IS NO MS GENE IN MY OPINION, it is a combination of normal gene variants that are designed to help us get though life, that in some combinations lead to MS. This is just like some combinations help us avoid the plague.

If you female you are twice as likely as a male to get MS, if you have the HLA gene associated with MS, you are only slightly more at risk than if you don't , the same is the case for each of the rest

Will there be a genetic test that tells you if you are going to get MS...The answer is NO!!!!!! and will always be NO!!!!. 

This is because, if you have 100% identical genes to those found in an Mser there is a 75% chance you will not get MS. Identical Twins studies told us this many, many, years ago.

2 comments:

  1. I wonder if it's wise to try to do statistical analyses on who -has- MS at this point. This can only currently be done based on who is -diagnosed- with MS which we know is very different from who -has- MS. Many patients aren't diagnosed until many years after even doctor's opinions, in hindsight, of when their first official symptom occurred. When the patient truly first contracted MS is still a huge mystery. 

    It's feasible that men could get MS just as often as women but are less likely to be diagnosed for purely sociological reasons, especially in more benign cases. There could be many, but an example would be men being potentially less likely to go to the doctor because of minor MS symptoms. Statistically, it's even probable that doctors are more likely to mis-diagnose men more often because of this perception that men are less likely to have MS. It's a self-fulfilling prophecy. 

    Like many people I went to the doctor multiple times with obvious MS symptoms (pars planitis and years later an unexplained limp and foot drop) without being diagnosed. I had much worse symptoms after that but didn't bother to see the doctor because past experience told me there was no point. It wasn't until I almost couldn't walk that I felt a doctor would be forced to figure out what was actually going on rather than just sending me home.

    Regardless of gender, it's possible that the number of people who actually have MS is two or three times the number of people diagnosed. It could be much more than that, we have no way of knowing. Anything's possible here because there's no deterministic method of diagnosing MS. 

    I comment now because I respect you, but you've posted multiple times about the statistics of who -has- MS but I want to point out that in that area, you literally have no idea what's going on (nobody does) and doctors have a very poor track record in this area of study. I don't know if much is to be gained by treating obviously and provably flawed statistics as truth. 

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  2. Lie Dam Lies and statisitics..... I will accept your proviso that there are people with MS that do not get diagnosed and so statistics always have some errors. Whilst men may be worse at going to doctors than women, I doubt this wholey explains the sex difference and the level in some places has been rising quite recently.

    However, I have heard a pathologist say that when doing post-mortems they found demyelination that looked like MS, Prof G may know the numbers of undiagnosed MSers but we had a clear example in the lab. I will make a post.

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