Muscular dystrophy causes

Last updated Aug. 28, 2025, by Lindsey Shapiro, PhD
✅ Fact-checked by Jose Lopes, PhD

 

Muscular dystrophy (MD) — a group of genetic muscle disorders marked by progressive muscle weakness and degeneration — is caused by mutations in genes that affect muscle health.

There are more than 30 different muscular dystrophy types, each caused by mutations in different genes. The specific mutation can affect the progression of MD symptoms and treatment strategies.

MD mutations are often inherited, passed down from parents to their biological children, but can sometimes occur spontaneously. There is no way to prevent MD.

What causes muscular dystrophy?

MD is caused by genetic defects that disrupt the production of proteins important for healthy muscle function. Consequently, muscles weaken and break down over time, driving the main MD symptoms.

Genetic mutations

Genes are made up of DNA sequences that provide the body with a template for making proteins. When there are changes in the normal sequence, called mutations, it can result in:

  • too little or too much protein being made
  • a protein that’s unstable or doesn’t work as it should.

In the case of MD, genetic mutations affect proteins important for muscle health. This genetic basis is the reason that genetic testing is the definitive way to establish an MD diagnosis.

Inheritance patterns

Most cases of MD arise when children inherit disease-causing mutations from their parents. There are three main patterns of MD inheritance:

X-linked inheritance means the mutation is found on the X chromosome, one of the two main sex chromosomes. These forms of MD occur predominantly in males.

  • Males have only one X chromosome, so a mutation in their only copy of the gene will result in MD.
  • Females have two X chromosomes, and both copies of the gene must be affected for MD to manifest. Carriers have only one copy mutated, so symptoms are unlikely, but the mutation can be passed on to their children.

Autosomal inheritance means the genetic issue is on a chromosome other than X or Y. People typically have two copies of these chromosomes, so these forms of MD affect males and females equally. The two types are:

  • autosomal recessive, both copies of the gene have to be mutated for MD to occur.
  • autosomal dominant, one mutated copy of the gene is enough for MD to occur.

Causes by type of muscular dystrophy

While all forms of MD cause muscle weakness, the underlying genetic causes of MD vary by disease type. Below is a list of the main types of MD and their causes.

Duchenne muscular dystrophy (DMD)

Duchenne muscular dystrophy (DMD), the most common form of MD, is caused by mutations in the DMD gene that result in a complete or near complete loss of dystrophin, a protein that protects muscles from damage. It is inherited in an X-linked manner.

There are a variety of mutation types that can lead to DMD. The specific DMD cause in an individual case may inform which MD treatment is chosen, as certain medications are meant to treat people with specific mutations.

Becker muscular dystrophy (BMD)

Becker muscular dystrophy (BMD) is also caused by DMD gene mutations that are inherited in an X-linked manner.

BMD-causing mutations lead to more dystrophin production, but the protein either doesn’t work quite right or there’s still not enough of it to maintain muscle health. As such, BMD has similar symptoms to DMD, but is typically milder.

Myotonic dystrophy

Myotonic dystrophy is caused by abnormally expanded segments of DNA in certain genes:

  • Myotonic dystrophy type 1 is caused by mutations in the DMPK gene.
  • Myotonic dystrophy type 2 is caused by mutations in the CNBP gene, also called ZNF9.

Normally, DNA is transcribed into a template molecule called messenger RNA that’s then used to produce proteins. But these DNA expansions in myotonic dystrophy lead to an abnormal RNA molecule that toxically accumulates and interferes with protein production.

Myotonic dystrophy is inherited in an autosomal dominant manner.

Limb-girdle muscular dystrophy (LGMD)

There are several types of limb-girdle muscular dystrophy (LGMD), characterized by muscle wasting at the shoulders and the hips. Each is caused by mutations in different genes that are important for muscle function and health. Some of the more common ones include:

  • CAPN3
  • DYSF
  • SGCA, SGCB, SGCG, and SGCD.

LGMD is inherited in an autosomal dominant or recessive pattern, depending on the disease subtype.

Facioscapulohumeral muscular dystrophy (FSHD)

Facioscapulohumeral muscular dystrophy (FSHD) is caused by alterations in a section of DNA on chromosome 4 called the D4Z4 region that result in the abnormal activation of the DUX4 gene. That gene’s protein product is toxic to muscle cells.

There are two types of FSHD:

  • Type 1 FSHD (95% of cases) is caused by an abnormal shortening of the D4Z4 region that reactivates DUX4.
  • Type 2 FSHD is usually caused by mutations in a gene called SMCHD1 that normally helps turn off the D4Z4 region.

FSHD is most commonly inherited in an autosomal dominant manner.

Congenital muscular dystrophy (CMD)

Congenital muscular dystrophy (CMD) can be caused by mutations in several different genes, many of which are important for muscle cell structure. They are often inherited in an autosomal recessive way, but sometimes may be autosomal dominant.

Examples of genes implicated in CMD include:

There are also various other forms of CMD, each caused by unique genetic abnormalities.

Emery-Dreifuss muscular dystrophy (EDMD)

Emery-Dreifuss muscular dystrophy (EDMD) can be caused by mutations in genes that produce proteins for the membrane that surrounds the nucleus of muscle cells, namely EMD, FHL1, or LMNA.

Mutations in EMD and FHL1 are inherited in an X-linked recessive pattern. LMNA mutations are usually inherited in an autosomal dominant pattern, but can be autosomal recessive.

Oculopharyngeal muscular dystrophy (OPMD)

Oculopharyngeal MD (OPMD) is caused by PABPN1 gene mutations that result in production of an abnormal protein that clumps up in muscle cells and disrupts their function.

OPMD is usually inherited in an autosomal dominant pattern, but is sometimes autosomal recessive.

Distal muscular dystrophy

Distal muscular dystrophy refers to a group of conditions caused by various genetic abnormalities that affect muscle health. Genes associated with forms of distal MD include:

  • TTN, tibial MD
  • TIA1, Welander distal myopathy
  • DYSF, Miyoshi distal myopathy
  • GNE, Nonaka distal myopathy
  • MYH7, Gowers-Laing distal myopathy
  • MATR3, distal myopathy with vocal cord and pharyngeal weakness
  • VCP, VCP myopathy.

Most forms are inherited in an autosomal dominant pattern, but some may be autosomal recessive.

Spontaneous mutations

While most cases of MD are directly inherited from a parent, there is not always a family history. Sometimes, the disease-causing mutation can occur spontaneously, or de novo, in an egg or sperm cell from a parent, or directly in the cells of a fertilized egg after conception.

De novo mutations happen by chance and there is no way to predict them. About a third of DMD cases are spontaneous.

Once MD appears spontaneously in a person, they can subsequently pass the mutation on to their own children following the typical inheritance pattern of their specific MD type.

Risk factors

A family history is the strongest predictor of MD, though there are few other established MD risk factors. When the disease runs in the family, certain individuals may be at a higher risk:

  • Males are substantially more likely to be affected by X-linked forms of MD such as DMD, BMD, and some types of EDMD.
  • The risk of forms of MD that usually present in young children, such as DMD, goes down as a person approaches adulthood without symptoms.

The genetic mutations that are the underlying MD causes can occur in people of all races and ethnicities, but certain types are seen more commonly in particular groups. For example, Fukuyama CMD is most common in Japanese populations, while OPMD is most common in French-Canadian populations.

Muscular Dystrophy News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

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