There are more than 30 types of MD, each with features that are unique in some way. Brief descriptions of some common (sometimes called “primary”) types of MD and a few of their symptoms are included here.1
For more detailed information about MD types and symptoms, visit the National Institute of Neurological Disorders and Stroke website, Muscular Dystrophy: Hope Through Research.
- DMD is the most common and severe form of MD among children, and it accounts for approximately half of MD cases.
- DMD occurs mostly in boys, usually between 3 and 5 years of age, and progresses rapidly. Most people with DMD are unable to walk by age 12 and may eventually need a respirator to breathe.
- Muscle weakness usually begins in the upper legs and pelvis.
- In the past, people with DMD usually died in their late teens or early 20s from heart trouble, respiratory complications, or infection. However, improvements in care mean that many people with DMD now live into their 30s or even 40s.
- Becker MD is caused by the dystrophin gene, like DMD, but usually has milder symptoms than DMD does.
- It occurs mostly in boys and men, usually between 11 and 25 years of age, and can progress slowly or quickly.
- Some people with Becker MD may never need to use a wheelchair, while others lose the ability to walk during their teens, during their mid-30s, or later.
- This is the most common adult-onset form of MD and usually affects people between 20 and 30 years of age, although it can also occur in children.2
- There are two types of myotonic MD: type 1 (more common) and type 2.3
- The primary symptom in both types is that muscles cannot relax following a sudden contraction.
- The name of this type of MD refers to the body areas affected: the face (facio), the shoulders (scapulo), and the upper arms (humeral).
- FSHD often appears first in the eyes—as difficulty opening and closing the eyelids—and the mouth—as being unable to smile or pucker the lips. Symptoms can vary from mild to severely disabling.
- FSHD mainly occurs during the teen years but may occur as late as age 40.
- Most people with FSHD have a normal life span.
- It can be inherited in an autosomal dominant manner.
- This type of MD affects males and females usually in adolescence or young adulthood, although it can begin in childhood.4
- Limb-girdle MD can progress quickly or slowly, but most patients become severely disabled (with muscle damage and the inability to walk) within 20 years of developing the disease.
- It is usually inherited in an autosomal recessive manner.
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