Muscular Dystrophy

What is Muscular Dystrophy?

Muscular dystrophy refers to a group of genetic, hereditary muscle diseases that cause progressive muscle weakness.

Muscular dystrophies are characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue. Nine diseases including Duchenne, Becker, limb girdle, congenital, facioscapulohumeral, myotonic, oculopharyngeal, distal, and Emery-Dreifuss are always classified as muscular dystrophy but there are more than 100 diseases in total with similarities to muscular dystrophy.

Most types of MD are multi-system disorders with manifestations in body systems including the heart, gastrointestinal and nervous systems, endocrine glands, skin, eyes and other organs.

The best-known type, Duchenne muscular dystrophy (DMD), is inherited in an X-linked recessive pattern, meaning that the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes, and is thus considered sex-linked. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition.

In females (who have two X chromosomes), a mutation must generally be present in both copies of the gene to cause the disorder (relatively rare exceptions, manifesting carriers, do occur due to dosage compensation/X-inactivation).

Males are therefore affected by X-linked recessive disorders much more often than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In about two thirds of DMD cases, an affected male inherits the mutation from a mother who carries one altered copy of the DMD gene. The other one third of cases probably result from new mutations in the gene. Females who carry one copy of a DMD mutation may have some signs and symptoms related to the condition (such as muscle weakness and cramping), but these are typically milder than the signs and symptoms seen in affected males. Duchenne muscular dystrophy and Becker's muscular dystrophy are caused by mutations of the gene for the dystrophin protein and lead to an overabundance of the enzyme creatine kinase. The dystrophin gene is the largest gene in humans.

Types of Muscular dystrophy

Becker's muscular dystrophy

Congenital muscular dystrophy

Duchenne muscular dystrophy

Distal muscular dystrophy

Emery-Dreifuss muscular dystrophy

Limb-girdle muscular dystrophy

Myotonic muscular dystrophy

Oculopharyngeal muscular dystrophy

Symptoms of Muscular dystrophy include:

Progressive Muscular Wasting (weakness)
Poor Balance
Frequent Falls
Walking Difficulty
Waddling Gait
Calf Pain
Limited Range of Movement
Muscle Contractions
Respiratory Difficulty
Drooping Eyelids (ptosis)
Gonadal Atrophy
Scoliosis (curvature of the spine)
Inability to walk
Some types of Muscular Dystrophy can affect the heart, causing cardiomyopathy or arrhythmias.

The prognosis for people with muscular dystrophy varies according to the type and progression of the disorder. Some cases may be mild and progress very slowly over a normal lifespan, while others produce severe muscle weakness, functional disability, and loss of the ability to walk. Some children with muscular dystrophy die in infancy while others live into adulthood with only moderate disability. The muscles affected vary, but can be around the pelvis, shoulder, face or elsewhere. Muscular dystrophy can affect adults, but the more severe forms tend to occur in early childhood.

Treatment

There is no known cure for muscular dystrophy. Inactivity (such as bed-rest and even sitting for long periods) can worsen the disease. Physical therapy, Occupational therapy, speech therapy and orthopedic instruments (e.g., wheelchairs, standing frames) may be helpful.

There is no specific treatment for any of the forms of muscular dystrophy. Physical therapy to prevent contractures (a condition when an individual with a muscular dystrophy grows and the muscles don't move with the bones and can easily be slowed down and/or make the individual's body straighter by daily physical therapy), orthoses (orthopedic appliances used for support) and corrective orthopedic surgery may be needed to improve the quality of life in some cases. The cardiac problems that occur with Emery-Dreifuss muscular dystrophy and myotonic muscular dystrophy may require a pacemaker. The myotonia (delayed relaxation of a muscle after a strong contraction) occurring in myotonic muscular dystrophy may be treated with medications such as quinine, phenytoin, or mexiletine but no actual long term treatment has been found.

Further Information Regarding Muscular Dystrophy

Myotonic Dystrophy Information
Myotonic Dystrophy (DM) is a progressive disease involving muscle weakness in which the muscles are slow to relax after contracting. DM is also referred to by additional names; "Myotonia Atrophica, " Dystrophia Myotonica," or, "Steinert's Disease," and is a common form of Muscular Dystrophy. DM affects both females and males nearly equally, and is an inherited disease.

Limb-Girdle Muscular Dystrophy
Limb-Girdle Muscular Dystrophy includes a group of diverse disorders which affect the voluntary muscles, predominantly around the person's pelvic and shoulder areas. On occasion the person's heart and breathing muscles may be involved as well. Various types of LGMD differ in their severity, the age at which onset occurs, and the manner in which they are inherited. The type of genetic alteration involved is the reason for the variation.

Congenital Muscular Dystrophy Information
Congenital Muscular Dystrophies (CMD's) are a group of diseases of the muscles. Both understanding and technology related to these diseases are progressing, and CMD's are going from being poorly understood subsets of Muscular Dystrophy to diseases that are more clearly defined.

Becker's Muscular Dystrophy Information
Becker's Muscular Dystrophy is a form of inherited disorder that is characterized by slow, progressive muscle weakness which a person experiences in both their pelvis and their legs. Becker's Muscular Dystrophy is also known as, "Benign Pseudohypertrophic Muscular Dystrophy." The disorder is similar to Duchenne's Muscular Dystrophy with the difference being that it tends to progress more slowly.

Duchenne Muscular Dystrophy and Pain
Duchenne Muscular Dystrophy (DMD) is one of the types of muscular dystrophy, a group of genetic, degenerative diseases primarily affecting voluntary muscles, and caused by an absence of dystrophin, a protein that helps keep muscle cells intact. This article also examines Duchenne muscular dystrophy pain.

Muscular Dystrophy Facts
The major problem with MD is that over time, it weakens the muscles. Because of this children, teens and adults who have been diagnosed with the disease will gradually lose their ability to do most of the things that we usually take for granted, such as: walking around, standing or sitting up. The muscle problems can affect a baby or the symptoms might begin later in life and it is not uncommon for adults to develop the disease.