Benign multiple sclerosis (MS) is a mild course of MS seen in 5-10% of MS patients. In people affected by benign MS, there is no worsening of functional ability even after 15 years of diagnosis. Currently, there is no way of predicting this form of MS at the time of diagnosis.
Studies have demonstrated that a benign course of MS is characterized by the absence of relapses and stable disability after 20-30 years of diagnosis. Benign MS patients usually have very few relapses followed by full recovery, and the effects of the condition are more sensory than mobility related.
Benign MS and disease progression
In an attempt to define benign MS, studies will often measure disease progression. Some skeptics feel that the term “benign” isn’t appropriate as the disease eventually progresses and becomes worse.
Neurologists widely use the expanded disability status scale (EDSS) to recognize benign MS. The EDSS measures the level of physical disability in a patient. A low EDSS score (3 or less) may be indicative of benign MS. Such a score would mean that the patient can walk around—though mild disability is present—over 10 years following diagnosis.
The impact of EDSS scores on therapy choices is high. To avoid the possibility of drug side effects, neurologists often defer treatment in people affected with benign MS until they start expressing severe symptoms.
Symptoms of benign MS
While physical disability is a symptom of benign MS, there are lesser-known symptoms of the disease. These symptoms include:
- Cognitive issues
- Loss of short-term memory
- Concentration impairment
Research on benign MS
A study published in the Journal of Neurology, Neurosurgery & Psychiatry aimed to establish the characteristics of benign MS and assess key prognostic factors. The study was carried out in parts of Northern Ireland and included 259 MS patients, of which 181 had MS for over 10 years and 36 had benign MS more than 10 years after onset.
On comparison of clinical and demographic data of the patient groups, the study identified 33 patients with benign MS. The results of the study showed that younger women are more susceptible to benign MS and 33.3% of them experienced sensory and optic neuritis as the most common symptoms.
In the case of people with late onset, progressive forms of MS were more likely than a benign course and these patients presented with motor disturbance. A follow-up study confirmed that benign MS patients had a mild course than non-benign forms, though it was concluded that the label “benign MS” is mostly temporary as progression of disability was significant.
Role of genes in benign MS
According to a new study, people with benign MS have a unique pattern of gene activity represented by the slowing of a key protein synthesis pathway that eventually leads to cell apoptosis.
The team of researchers from Sheba Medical Center in Israel compared the gene expression profile of benign MS and relapsing-remitting MS (RRMS) patients. Blood cells from 36 RRMS patients and 31 benign MS patients (after 17 years of diagnosis and <3 EDSS score) were collected.
On comparison of the two groups using microarrays, 406 genes were found to be different and over 50% of these genes were less active in the case of patients with benign MS. The researchers found that less active genes were linked to the RNA polymerase I (Pol I) pathway, which synthesizes several components of the ribosome.
Researchers also found that benign MS patients had an overactive p53 pathway, which promotes cell death, causing the suicide of self-reactive immune cells. According to the team, this may explain why symptoms are less severe in benign MS.