The Muscular dystrophy refers to a heterogeneous group of diseases that cause hereditary genetic and progressive degeneration of skeletal muscles, with consequent weakness and loss of autonomy in voluntary movement.

These are rare disorders, the first symptoms of which usually appear in childhood. There are different varieties of muscular dystrophy . Each one of them presents specific characteristics, severity and particular ages of appearance.

All forms of muscular dystrophy get worse as the muscles progressively degenerate and weaken.

Most patients eventually lose the ability to walk, and even in some cases life may be compromised by requiring ventilatory support due to the inability of respiratory movements. The most common form is  Duchenne muscular dystrophy, which affects males and is genetically transmitted by mothers as it is X-linked recessive inheritance .

What Causes Muscular Dystrophy?

The muscular dystrophies are transmitted by heredity and involve a mutation in the gene responsible for programming the proteins necessary for muscle integrity. In some more particular cases of muscular dystrophy they can occur secondary to spontaneous mutations that are not found in the paternal genes but that can be transmitted to the next generation.

Genes are organized along twenty-three pairs of  chromosomes , with one half of each pair inherited from each parent. Each chromosome is similar to the other, with the exception of the pair that determines the sex of the individual. Consequently, muscular dystrophies can be inherited in three ways:

  • Autosomal dominant inheritance  (when the disease is transmitted and manifested through a single affected chromosome).
  • Autosomal recessive inheritance  (when the defective gene must be transferred from both parents to express the disease
  • X-linked or sex-linked recessive inheritance, which is what occurs with Duchenne muscular dystrophy, in which females are carriers in 50% of cases and males express it by having only one X chromosome .

Signs and symptoms of muscular dystrophy

Regardless of the type of muscular dystrophy , the main presenting sign is generalized muscular weakness that becomes progressive and, in some cases, exponential. The other specific signs and symptoms begin at different ages and in different muscle groups, depending on the type of muscular dystrophy .

In the case of Duchenne muscular dystrophy, the signs and symptoms can be evidenced in early stages of life such as early childhood, sudden and repeated falls being common in these children or young people, presenting difficulty in reincorporation, as well as , in the case of changing position (lying upright). Other symptoms that may be observed include:

  • Clumsiness and difficulty when running and jumping.
  • Walking on toes or duck gait (rocking gait caused by exaggerated hip scale and foot separation to increase base of support and balance).
  • Stiffness and muscle pain.
  • Loss of some reflexes.
  • Pseudohypertrophy in some muscle groups such as the gastrocnemius muscles (calves) where it impresses with greater muscle size, but it is due to the fat and connective tissue replacement of the worn muscle.
  • Mental impairment
  • Shortness of breath
  • Cardiomyopathy

In the case of Becker muscular dystrophy , the signs and symptoms are similar to those described above, but they tend to be milder and progress more slowly. Symptoms usually begin in adolescence, but may even manifest later.

In so-called congenital muscular dystrophy, muscle weakness may be noticed first, when children do not meet expected goals for months of life in terms of motor function and muscle control.

The muscle degeneration may be mild or severe and is restricted primarily to skeletal muscle, being in some affected children never learn to walk.


Unfortunately, there is no cure for this disease. However, there are drugs that can help improve muscle pain, associated with non-steroidal anti-inflammatory pain relievers, associated with physical rehabilitation to reduce muscle atrophy and improve range of motion.

It is important to go to the doctor to make an early diagnosis and indicate treatment to improve the quality of life of these patients.

By Dr. Eric Jackson

Dr. Eric Jackson provides primary Internal Medicine care for men and women and treats patients with bone and mineral diseases, diabetes, heart conditions, and other chronic illnesses.He is a Washington University Bone Health Program physician and is a certified Bone Densitometrist. Dr. Avery is consistently recognized in "The Best Doctors in America" list.

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