What is Myotonic Dystrophy?

Article Details
  • Originally Written By: Jacquelyn Gilchrist
  • Revised By: C. Mitchell
  • Edited By: Michelle Arevalo
  • Last Modified Date: 07 April 2019
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Myotonic dystrophy is a medical condition in which a person’s muscle fibers weaken and disintegrate over time, leading to stiffness and eventual paralysis in some patients. It’s a genetically acquired disease that people can develop at basically any point in life. Depending on the severity and when it sets in, sufferers can lead fairly normal lives, though babies who are born with it don’t often survive for long. The main symptoms are muscle deterioration and weakness, as well as heart palpitations and related blood circulation problems. Medical experts haven’t identified a cure for this disease, though there are many treatment options to help patients feel comfortable and manage their symptoms.

Why it Happens

People develop myotonic dystrophy, which is also known as Steinert's disease or myotonic muscular dystrophy (MMD), as a result of inherited genetic abnormalities. In simpler terms this means that people have to get it from either their mother, their father, or both — it isn’t contagious and doesn’t just happen on its own.

Researchers believe that the coding for MMD happens on the chromosomal level, and it’s caused by either one or two mutated genes. Patients who have a mutation in chromosome 19 have a form of MMD called type 1. Type 2 MMD is caused by a mutation in chromosome 3.


Main Symptoms

The primary symptom of this condition is muscle weakening that leads to myotonia, an involuntary muscle tension problem. Weakening muscles are often hard to control, and as the fibers break down during deterioration and nerve signals are often confused or lost as a result. This can lead to an inability to relax the muscles and can make a person feel unusually stiff.

Aside from involuntary muscle tension, other possible symptoms and complications of MMD include weak muscle tone, or hypotonia, and developmental delays. Men who suffer from MMD may experience balding due to hormonal changes rather than aging. They may also suffer from infertility.

Vision Problems

Cataracts are also common among MMD patients. A cataract is an eye condition in which the lens of one but usually both eyes begin to cloud over. If untreated, this cloudiness usually gets steadily worse until a person is basically blind, or at least unable to see anything with the clarity needed to identify or distinguish it.

Heart Complications

The heart is one of the strongest muscles in the body, which makes it particularly susceptible to the breakdown and weakening problems so common with this disease. Patients frequently experience heart arrhythmia in the early stages of MMD onset. This condition causes an abnormality in a person's heart rhythm. In many people this sort of abnormaility is so minor as to not really cause problems, but medical experts often pay particularly close attention to heart patterns over time when patients have degenerative conditions in order to catch signs of failure and major deterioration early on. Patients with heart arrhythmia due to MMD may require medication, a pacemaker, or regular heart monitoring to prevent major cardiac incidents.

Progress and Speed of Deterioration

It’s important to note through all of this that the severity of symptoms from MMD can vary widely. The disease is classed as “progressive,” which means that as a person ages, the symptoms typically become worse. Some patients progress more quickly than others. Children who are born with the condition don’t often survive past infancy, and in these cases the disease is more formally known as congenital myotonic dystrophy. Babies in this situation often experience muscle deterioration before those muscles ever really have a chance to develop, which can cause major heart and respiratory problems. If they do live into childhood, kids with this disorder run the risk of developing learning disabilities.

In other cases, however, a patient may live for 50 or 60 years with the disease before experiencing many debilitating symptoms, and even then problems may be slow to develop and take hold. A lot depends on personal health history, the specifics of the genetic mutation, and the environment. Researchers still aren’t sure about many of the causes and triggers for the condition’s most debilitating symptoms.

Treatment and Care Options

There is no known cure for myotonic dystrophy, or any other form of muscular dystrophy for that matter. In most cases, treatments are generally intended to ease symptoms and help stall the deterioration that is coming at some point. For example, a patient may undergo surgery to correct a cataract to improve his vision, and physical therapy may help improve muscle tone and strength and maintain flexibility in the joints. Some medications can also alleviate myotonia and slow muscle degeneration. It’s usually true that starting treatment as soon as the disease is discovered allows for the most successful results. As such, anyone who is concerned about muscular issues or is noticing anything unusual about their movements or muscle control is encouraged to get a check-up.



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