Is MS hereditary?

MS is a term used to describe the disease multiple sclerosis. MS is a disease of the central nervous system. The central nervous system is made up of the brain and the spinal cord with its connections. In MS, the communication between the brain and other parts of the body through the nerves is intercepted. It is believed to be an autoimmune disease. In autoimmune diseases, the body develops antibodies and begins a defensive attack against its own tissues. In MS, the attack is launched against the tissue which serves as an insulating coating for the nerves (myelin sheath). This affects the sensation they covey to various body tissues they supply. The term “multiple sclerosis” refers to the many areas of scarring (sclerosis) that result from the destruction of the myelin sheath in the brain and spinal cord. This destruction is called demyelination. Sometimes the nerve fibers that send messages are also damaged, this may lead to the brain shrinking in size over time.

MS affects approximately 400,000 people in the United States and 2.5 million worldwide. More than 200 people are diagnosed with MS each week in the United States. In North America and Europe, an estimate of greater than 100 people per 100,000 population have MS while it is very low in Eastern Asia and sub-Saharan Africa (about 2 people per 100,000 population).

What are the signs and symptoms of MS?

MS often occur in young people. The first symptoms are usually experienced between the ages of 15 to 60 years. It is commoner in women than men and largely uncommon in children.

It usually starts as visual disturbances like blurry vision or double vision, blindness in one eye, or difficulty differentiating between red and green colours. Another early symptoms is tingling, pain, burning, and itching in the arms, legs, trunk, or face and sometimes a reduced sense of touch.

Other symptoms are:

  • Weakness in the hands and feet
  • Difficulty in keeping a good balance and coordination often leading to frequent falls
  • Difficulty in walking due to paralysis of the lower limb muscles
  • Distortion of sensations (paraesthesia) like feeling numbness, prickly, or pins and needle sensations on the hands and feet.
  • Speech difficulties
  • Dizziness
  • Tremors
  • Hearing loss
  • Poor concentration
  • Depression
  • Cognitive impairment
  • Inability to control emotions normally
  • Urinary tract issues like Frequent and strong urges to urinate, Involuntary passage of urine (urinary incontinence), Difficulty starting to urinate and Inability to empty the bladder completely.
  • constipation

Most times the symptoms of MS reduce or ‘disappear’ and the sufferers have periods of relatively good health (remissions) which alternates with periods of worsening symptoms (flare-ups or relapses). Relapses can be mild or debilitating. MS symptoms however, progressively worsen over time.

What causes MS?

The cause of MS is largely unknown but is believed to be as a result of a complex interplay between the immune system; and genetic and environmental factors.

Environment has been reported to play a role in MS. Where people spend the first 15 years of life affects their chance of developing MS. It occurs more in people who grew up in a temperate climate, than tropical climate and much less commonly in people who grew up near the equator. The exact reason is unknown but may be linked to the higher vitamin D levels in people whose skin are more exposed to sunlight like in the tropics and close to the equator.

It is also interesting that where people live later in life (regardless of climate), does not change their chances of developing multiple sclerosis.

Smoking also increases the chances of developing MS.

Is MS hereditary?

Even though MS is not an exactly straight forward predictable hereditary disease (like the Mendelian model), researches have reported that genes play a very important role in its occurrence. An identical twin is 30% more likely to have the disease if the other twin has it, and about 15 to 20 % of people that have MS had a family member who suffered from the disease.

The lifetime risk is also greater among first degree relatives than second and third degree relatives. The risk of MS is also markedly higher if both parents have MS and the risk of half-siblings is lower than that of full siblings. These show that the risk of MS increases among individuals who share similar genes, though the exact pattern is not known.

What is the treatment of MS?

Currently there is no cure for MS. A lot of people with mild disease do well with no medications at all, and are only monitored by the doctors. However, some steroid drugs may be given to treat the acute symptoms of an attack. There are many other approved drugs which are also used to decrease attack frequency and severity, treating relapses, or delaying progression. A lot of these drugs are potentially toxic and have serious side effects. They are only given by professionals and individuals on them are monitored closely for these side effects.

So when you or a family member have some of the symptoms listed above, do well to quickly book for a doctor’s appointment for proper evaluation.