Multiple sclerosis (MS) is an idiopathic autoimmune neurodegenerative disease in which dysregulation of the immune system causes myelin sheath degradation. Multiple sclerosis is characterized by plaques or lesions in the brain and spinal cord. The location and size of the lesions is unpredictable. Symptoms of Multiple Sclerosis include affected coordination, balance and vision, and disturbances in the bowel, bladder and sexual organs.
Disease onset is typically between the ages of 20 and 40. Women have a 2 -3 fold higher incidence of MS than men. The distribution of MS inversely parallels the global distribution of UV light, suggesting a role for vitamin D in the disease.
- Visual changes including double vision or loss of vision
- Tingling or weakness (weakness may range from mild to severe)
- Vertigo or dizziness
- Erectile dysfunction (ED, impotence)
- Pregnancy problems
- Urinary incontinence (or conversely, urinary retention)
- Muscle spasticity
- In coordination of muscles
- Painful involuntary muscle contractions
- Slurred speech
Exact cause is not known.
- It is suspected to be immune system malfunction
- Body’s immune system mistakenly attacks myelin sheath of the nerve cells
- Myelin sheath is a protective covering around the nerve cell which will help in the transmission of signals
- Once the myelin sheath is damaged, signal transmission become slow or blocked
- Sometimes nerve damage may also occur
- Genetics and environmental factor may also play a role
It is not currently known how to prevent multiple sclerosis. Frequency of relapse or remitting condition can be minimized by taking medication.
Complications may include the following:
- Muscle stiffness or spasms
- Paralysis, typically in the legs
- Problems with bladder, bowel or sexual function
- Mental changes, such as forgetfulness or mood swings
The main value of genetic testing in MS is to provide insights into the mechanism of the disease, thereby potentially suggesting strategies for prevention and treatment, rather than as a diagnostic tool. First degree relatives of patients with MS are generally at 20 – 40 times greater risk of developing the disease themselves, compared to the general population, showing that the disease has a large genetic component. HLA-DRB1*15:01 is a disease susceptibility gene, accounting for up to 35% of the heritability of the disease.
Homozygosity for this haplotype increases disease risk six fold. The exact mechanism by which HLA increases the susceptibility to MS is unknown. A recent finding of a vitamin D response element in the promoter region of HLA-DRB1, which is completely conserved in HLA-DRB1*15:01, together with evidence showing that vitamin D is significantly lower in MS patients is suggestive of combined effects of HLA-DR15:01 inheritance and vitamin D exposure on MS risk.
- Banwell BL. Pediatric multiple sclerosis. Curr Neurol Neurosci Rep. 2004; 4:245.
- Friese MA et al. Opposing effects of HLA class I molecules in tuning autoreactive CD8+ T cells in multiple sclerosis. Nat Med. 2008; 14:1227.
- Lincoln MR et al. A predominant role for the HLA class II region in the association of the MHC region with multiple sclerosis. Nat Genet. 2005; 37:1108.
- Nolan D et al. Contributions of vitamin D response elements and HLA promoters to multiple sclerosis risk. Neurology. 2012; 79:538.
- Ramagopalan SV et al. Expression of the multiple sclerosis-associated MHC class II Allele HLA-DRB1*1501 is regulated by vitamin D. PLoS Genet. 2009; 5:e1000369.
- Renoux C et al. Natural history of multiple sclerosis with childhood onset. N Engl J Med. 2007; 356:2603.
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