Muscular Dystrophy Types

Muscular dystrophies are a heterogeneous group of hereditary illnesses affecting both children and adults, with at least 30 different genes responsible for the disease development. These conditions are characterized by muscle wasting and weakness and may be associated with cardiomyopathy with an increased risk of sudden cardiac death.

Image Credit: Freedom Studio / Shutterstock.com

Dystrophinopathies

Dystrophinopathies are muscle diseases caused by pathogenic variants in the gene DMD which encodes the protein dystrophin. The severe end of the spectrum includes two diseases that include Duchenne and Becker muscular dystrophy, whereas the mild end of the spectrum can manifest only with an increased serum concentration of creatine phosphokinase (CK), myoglobinuria, and occasional muscle cramps.

Duchenne muscular dystrophy represents a severe, progressive disease that affects 1 in 3,600–6,000 live male births. It is one of the most severe muscle diseases to affect children. The majority of patients are unable to run and jump adequately due to proximal muscle weakness, which also results in the use of the classic Gowers maneuver when arising from the floor.

Muscle weakness in Duchenne muscular dystrophy can begin as early as in the fourth year of life, initially affecting the pelvic area, hip muscles, thighs, and shoulders. By the early teenage years, the heart and respiratory muscles are also affected. The disease is rapidly progressive, with affected children being wheelchair dependent by the age of 13.

Becker muscular dystrophy is usually milder and more varied as compared to Duchenne muscular dystrophy. In most cases, muscle weakness becomes obvious later in childhood or in adolescence, and muscle deterioration occurs at a much slower rate. This type of muscular dystrophy occurs in about 3 to 6 out of every 100,000 live male births.

Congenital muscular dystrophy

Congenital muscular dystrophies represent a mixed group of conditions with varying degrees of severity and progression rates. These conditions are characterized by diminished muscle tone at birth, otherwise known as congenital hypotonia, delayed motor development, spinal rigidity, early onset of progressive muscle weakness, and dystrophic pattern on muscle biopsy.

Congenital muscular dystrophy

The main subtypes of congenital muscular dystrophy, which are grouped according to the involved protein function and mutated gene, are laminin alpha-2 (or merosin) deficiency, collagen VI-deficient congenital muscular dystrophy, the dystroglycanopathies, SEPN1-related congenital muscular dystrophy, and LMNA-related congenital muscular dystrophy. Several lesser-known subtypes have also been reported in a small number of individuals.

Cognitive impairment that ranges from intellectual disability to mild cognitive delay, structural eye and brain abnormalities, as well as seizures, are almost exclusively found in dystroglycanopathies. Comparatively, white matter abnormalities without major cognitive involvement are usually seen in the laminin alpha-2-deficient subtype.

Myotonic dystrophy and other types

Myotonic dystrophy is considered the most common adult form of muscular dystrophy. Moreover, this form of muscular dystrophy is characterized by autosomal dominant progressive myopathy, myotonia, and the involvement of multiple organs. To date, two distinct forms of myotonic dystrophy caused by similar mutations have been identified, which require different diagnostic and management strategies despite their clinical and genetic similarities.

Other types of muscular dystrophy that can occur later in life include limb-girdle muscular dystrophy, distal muscular dystrophy, and ophthalmoplegic muscular dystrophy. The severity, age of onset, and features of these conditions vary significantly among the many subtypes, and may also be inconsistent even within the same family.

Facioscapulohumeral dystrophy is a form of muscular dystrophy that affects the face and shoulders. It is generally considered more benign than other forms of muscular dystrophy. Most cases arise due to a deletion near the end of chromosome 4, and symptoms develop in the teenage years.

References

Further Reading

Last Updated: Mar 23, 2021

Dr. Tomislav Meštrović

Written by

Dr. Tomislav Meštrović

Dr. Tomislav Meštrović is a medical doctor (MD) with a Ph.D. in biomedical and health sciences, specialist in the field of clinical microbiology, and an Assistant Professor at Croatia's youngest university - University North. In addition to his interest in clinical, research and lecturing activities, his immense passion for medical writing and scientific communication goes back to his student days. He enjoys contributing back to the community. In his spare time, Tomislav is a movie buff and an avid traveler.

Citations

Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Meštrović, Tomislav. (2021, March 23). Muscular Dystrophy Types. News-Medical. Retrieved on October 31, 2024 from https://www.news-medical.net/health/Muscular-Dystrophy-Types.aspx.

  • MLA

    Meštrović, Tomislav. "Muscular Dystrophy Types". News-Medical. 31 October 2024. <https://www.news-medical.net/health/Muscular-Dystrophy-Types.aspx>.

  • Chicago

    Meštrović, Tomislav. "Muscular Dystrophy Types". News-Medical. https://www.news-medical.net/health/Muscular-Dystrophy-Types.aspx. (accessed October 31, 2024).

  • Harvard

    Meštrović, Tomislav. 2021. Muscular Dystrophy Types. News-Medical, viewed 31 October 2024, https://www.news-medical.net/health/Muscular-Dystrophy-Types.aspx.

Comments

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment
Post

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.