Duchenne muscular dystrophy | |
---|---|
Microscopic image of cross-sectional calf muscle from a person with Duchenne muscular dystrophy, showing extensive replacement of muscle fibers by fat cells. | |
Pronunciation | |
Specialty | Pediatric neurology, neuromuscular medicine, medical genetics |
Symptoms | Muscle weakness, trouble standing up, scoliosis[2][3][4] |
Usual onset | Around age 4[2] |
Causes | Genetic (X-linked recessive)[3] |
Diagnostic method | Genetic testing[3] |
Treatment | Pharmacological treatment, physical therapy, braces, speech therapy, occupational therapy, surgery, assisted ventilation[2][3] |
Medication | Corticosteroids |
Prognosis | life expectancy of 21–40 years[5] |
Frequency | In males, 1 in 3,500-6,000[3] In females, 1 in 50,000,000[6] |
Duchenne muscular dystrophy (DMD) is a severe type of muscular dystrophy predominantly affecting boys.[3][7][8] The onset of muscle weakness typically begins around age four, with rapid progression.[2] Initially, muscle loss occurs in the thighs and pelvis, extending to the arms,[3] which can lead to difficulties in standing up.[3] By the age of 12, most individuals with Duchenne muscular dystrophy are unable to walk.[2] Affected muscles may appear larger due to an increase in fat content,[3] and scoliosis is common.[3] Some individuals may experience intellectual disability,[3] and females carrying a single copy of the mutated gene may show mild symptoms.[3]
Duchenne muscular dystrophy is caused by mutations or deletions in any of the 79 exons encoding the large dystrophin protein, which is essential for maintaining the muscle fibers' cell membrane integrity.[3] The disorder follows an X-linked recessive inheritance pattern, with approximately two-thirds of cases inherited from the mother and one-third resulting from a new mutation.[3] Diagnosis can frequently be made at birth through genetic testing, and elevated creatine kinase levels in the blood are indicative of the condition.[3]
While there is no known cure, management strategies such as physical therapy, braces, and corrective surgery may alleviate symptoms.[2] Assisted ventilation may be required in those with weakness of breathing muscles.[3] Several drugs designed to address the root cause are currently available including gene therapy (Elevidys), and antisense drugs (Ataluren, Eteplirsen etc.).[3] Other medications used include glucocorticoids (Deflazacort, Vamorolone); calcium channel blockers (Diltiazem); to slow skeletal and cardiac muscle degeneration, anticonvulsants to control seizures and some muscle activity, and Histone deacetylase inhibitors (Givinostat) to delay damage to dying muscle cells.[2][3]
Various figures of the occurrence of Duchenne muscular dystrophy are reported. One source reports that it affects about one in 3,500 to 6,000 males at birth.[3] Another source reports Duchenne muscular dystrophy being a rare disease and having an occurrence of 7.1 per 100,000 male births.[9] A number of sources referenced in this article indicate an occurrence of 6 per 100,000.[10]
Duchenne muscular dystrophy is the most common type of muscular dystrophy,[3] with a median life expectancy of 27–31 years.[5][11] However, with comprehensive care, some individuals may live into their 30s or 40s.[3] Duchenne muscular dystrophy is considerably rarer in females, occurring in approximately one in 50,000,000 live female births.[6]
:1
was invoked but never defined (see the help page).:2
was invoked but never defined (see the help page).