Back To Search Results

Becker Muscular Dystrophy

Editor: Krishna Kishore Umapathi Updated: 1/30/2024 2:19:43 AM


Becker muscular dystrophy (BMD) is an X-linked recessive disorder involving a mutation in the dystrophin gene. Progressive muscle weakness, most notably of the proximal lower limbs, is the primary manifestation of this condition.[1][2] The onset of BMD symptoms varies widely between 5 and 60 years. In a study involving 67 individuals with BMD, most were found ambulant until their 40s or older, while a small group experienced earlier loss of ambulation.[3] BMD symptoms usually appear at a later age than a similar X-linked disorder, Duchenne muscular dystrophy (DMD).

DMD and BMD may be easier to distinguish based on the age at which patients become wheelchair-dependent. Patients with DMD are wheelchair-dependent before age 13, while individuals with BMD may remain ambulatory even after age 16. Patients presenting with proximal muscle weakness before turning 12 may be hard to diagnose without genetic analysis.[4]

BMD is currently considered a mild form of DMD rather than a distinct clinical entity. Consequently, interventional trials are more rarely conducted for BMD than DMD.[5]

Skeletal muscle fibers (myocytes) arise from the fusion of contiguous embryonic muscle cells and are thus multinucleated. Multiple nuclei may be found close to the intracytoplasmic surface of the cell membrane (sarcolemma). Myocytes have abundant microfilaments, which give rise to the contractile apparatus of the myofibrils.

The repeating units of myofibrils are the sarcomeres, composed of interlaced actin and myosin filaments and perpendicularly oriented Z-bands. The T-tubule system is a sarcolemmal invagination into the myocyte involved in calcium storage and release during contraction. The sarcoplasm (myocyte cytoplasm) contains myoglobin, glycogen, creatine, creatine kinase (CK), lysosomes, mitochondria, and lipid vacuoles. 

Actin binds to the subsarcolemmal cytoskeletal protein dystrophin, which interfaces with the extracellular matrix through transmembrane dystrophin-associated proteins. Dystrophin normally provides mechanical reinforcement, stabilizing the cell membrane. Dystrophin abnormality is the leading cause of BMD.


Register For Free And Read The Full Article
Get the answers you need instantly with the StatPearls Clinical Decision Support tool. StatPearls spent the last decade developing the largest and most updated Point-of Care resource ever developed. Earn CME/CE by searching and reading articles.
  • Dropdown arrow Search engine and full access to all medical articles
  • Dropdown arrow 10 free questions in your specialty
  • Dropdown arrow Free CME/CE Activities
  • Dropdown arrow Free daily question in your email
  • Dropdown arrow Save favorite articles to your dashboard
  • Dropdown arrow Emails offering discounts

Learn more about a Subscription to StatPearls Point-of-Care


BMD arises from a mutation in the subsarcolemmal protein dystrophin. The defective gene is located in the Xp21.2 chromosome, and the defect is inherited as an X-linked recessive trait. Patients without a clear X-linked inheritance pattern may have defects in the genes encoding dystrophin-associated glycoproteins rather than dystrophin.

The dystrophin gene consists of 79 exons in Xp21 and spans more than 2200 kb.[6][7] Mutation is more likely during meiosis due to a large number of base pairs—around 2 million—involved. Other mutations, like small deletions, insertions, and small site variants, also occur less frequently.[8]

DMD mutations are often different from those involved in BMD. DMD arises mainly from out-of-frame mutations of the dystrophin open reading frame, resulting in a lack of dystrophin expression. BMD results from in-frame mutations, leading to dystrophin deficiency or dysfunction. Consequently, BMD has a much broader phenotypic presentation.

Immunohistoanalysis shows a complete absence of dystrophin in patients with DMD. Individuals with BMD have 10% to 40% of the normal dystrophin amount or have a partially functional form of the subsarcolemmal protein.[9]


BMD is a rare disease almost exclusively in male individuals due to X-linked inheritance. The condition is less common and less severe than DMD and is considered a milder allelic form of DMD. The worldwide prevalence of DMD and BMD ranges from 0.1 to 1.8 per 10,000 male individuals. A 2010 U.S. research revealed that BMD's prevalence for all age groups was 0.26 per 10,000 male individuals. Additionally, the condition was found to be more common among non-Hispanic white persons than non-Hispanic black persons.

A study of people with BMD suggests a prevalence of 0.01 in South Africa, 0.1 to 0.2 in Asia, and 0.1 to 0.7 in European countries per 10,000 male individuals. Isolated data shows BMD is 3 times less common than DMD.[10] However, sequencing studies show that BMD is underdiagnosed. Better dystrophin gene sequencing has allowed the identification of more patients with BMD and female carriers of dystrophin gene mutation.[11]


Dystrophin gene deletions (65% to 70%) or duplications (5% to 10%) result in dystrophin dysfunction or deficiency.[12] Disruption of the dystrophin-glycoprotein complex leads to cell membrane damage and myofiber degeneration. Sarcolemmal damage causes the outflow of CK and the influx of calcium ions in the myocytes.[13] Inflammatory mediators stimulate inducible nitric oxide synthase overexpression, increasing nitric oxide production. Nitrosylation destabilizes the ryanodine receptor of the sarcoplasmic reticulum, followed by calcium leakage in the cytosol. Increased cellular calcium ion concentration activates calpains that mediate protein degradation and progressive muscle weakness.[14][15] Complications like cardiomyopathy, joint contractures, and respiratory failure may arise from severe muscle wasting in the late stages of this illness.

BMD often presents with exercise-induced muscle weakness and fatigue. During exercise, the dystrophin-glycoprotein complex normally recruits neuronal nitric oxide synthase into the sarcolemma. This enzyme produces the vasodilator nitric oxide, which increases blood flow to the muscles to prevent fatigue. Dystrophin deficiency or dysfunction disrupts neuronal nitric oxide synthase recruitment and produces nitric oxide during intense physical activity.[16][17]


The hallmark of BMD on microscopic examination is ongoing myofiber necrosis and regeneration. Active muscle fiber necrosis and clusters of basophilic regenerating fibers are more prominent in younger patients. In contrast, myofiber splitting with necrosis, increased internal nuclei, fiber hypertrophy, fatty replacement, and endomysial fibrosis are more often found in older patients.[18][19]

History and Physical

BMD presents variably. When taking the clinical history, the onset of symptoms, precipitating and palliative factors, body areas affected, and symptom severity must be established. Family and developmental history must likewise be documented.

Children may present with proximal muscle weakness earlier than distal limb muscles. Lower limbs are affected earlier than upper limbs. Cramping with strenuous activity and gross motor milestone delays may also be reported. Growth can be slower, leading to short stature. Some patients may have cognitive impairment. The intelligence quotient of 20% to 25% of patients is less than 70. A positive family history may be elicited.

Some patients experience a late onset and retain ambulation until adulthood. Elbow fractures, cardiomyopathy, breathing difficulty, joint contractures, and toe-walking may be seen as the condition progresses. Cardiomyopathy is due to left ventricular wall fibrosis, which can cause life-threatening arrhythmias.

Rarely patients have elevated CK levels without any weakness. Other individuals may manifest neurologic symptoms instead of skeletal muscle involvement. Female carriers may only present with cardiomyopathy, though some may also have mild skeletal muscle weakness. Approximately 22% of carriers become symptomatic with a high degree of variability. Genetic analysis is required for proper diagnosis. 

Physical examination may reveal the following:[20][21][43]

  • Atrophy with pseudohypertrophy of the calf muscles
  • Quadriceps hypotonia, hyporeflexia, and fasciculations
  • Gowers sign or using the hands and arms to push the body upright from a squatting position
  • Lumbar lordosis
  • Achilles tendon shortening
  • Knee, elbow, or hip joint contractures
  • Macroglossia
  • Forearm muscle enlargement
  • Scoliosis due to progressive thoracic muscle weakness
  • Signs of cardiac involvement, such as jugular venous distension, cardiac impulse displacement, peripheral edema, S3 gallop, and mitral or tricuspid regurgitation murmurs 
  • Signs of respiratory failure in advanced cases, such as crackles, cyanosis, and low oxygen saturation

Muscle pseudohypertrophy is due to the fibrosis and fatty replacement of atrophic muscles, which are classical features of BMD.

All individuals with suspected BMD must have a detailed head and neck, musculoskeletal, and neurologic examination. Since patients have an increased risk of cardiorespiratory failure, a complete cardiovascular and respiratory examination should be performed during every consultation.


Proximal limb muscle weakness and distal limb hypertrophy in a male individual should increase suspicion of BMD, especially if family history is positive for the same condition. The mainstays of BMD diagnostic testing are CK level and dystrophin gene deletion analysis or muscle biopsy with dystrophin antibody staining. However, an invasive procedure like muscle biopsy is avoided in most instances, and genetic testing suffices for BMD confirmation.

CK Levels

High blood CK levels indicate muscle degeneration. CK levels peak at ages 10 to 15 years. Creatinine levels are likewise elevated five times or more than normal.

Genetic Analysis

Genetic analysis is usually sufficient for diagnosis and is thus commonly used in the modern era. This modality detects deletions and duplications by methods like multiplex ligation-dependent probe amplification, fluorescence in situ hybridization, and polymerase chain reaction.[22][23] Of these tests, multiplex ligation-dependent probe amplification is most frequently used for diagnosis. Muscle biopsy with dystrophin antibody staining may be useful if the result of genetic analysis is negative.

Genetic analysis should be performed first for diagnosis in patients with sporadic illness. Meanwhile, the diagnosis is straightforward in familial cases since gene mutation has already been determined.


Electromyography may help differentiate between a primary nerve disease process and myopathy. This diagnostic modality can identify the best muscle group for obtaining a biopsy specimen. However, electromyography is rarely used in diagnosis.

Muscle Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) can aid in the diagnosis and progress assessment of all dystrophinopathies (see Image. Cross-sectional Magnetic Resonance Images at Baseline and on Follow-Up of a Patient with Becker Muscular Dystrophy). MRI is especially helpful in outcome measure analysis in clinical trials. This modality is a non-invasive means of visualizing fatty infiltration, muscle loss, edema from ongoing muscle damage, and fibrosis. The pattern of muscle involvement can help define different types of muscle diseases. Dystrophinopathies are characterized by glutei and adductor magnus involvement while sparing the sartorius and gracilis.[24]

Muscle Biopsy

Muscle histology reveals muscle necrosis and regeneration, fatty replacement, and endomysial fibrosis. However, these findings are not specific to BMD. Genetic analysis is still preferred for confirming the diagnosis.[25]


BMD predisposes patients to cardiac disease. Electrocardiography is an excellent test for initial cardiac function evaluation in affected individuals. This modality can help detect supraventricular and ventricular arrhythmias early in symptomatic patients.


Transaminases may be elevated in the presence of muscle pathology. Pulmonary function tests may be obtained since BMD can cause respiratory muscle dysfunction. Spinal radiographs can help follow scoliosis progression, which may result from progressive trunk muscle weakness. These modalities are unnecessary for BMD diagnosis but may be recommended depending on patient presentation.

Treatment / Management

BMD has no cure. Gene therapy for restoring normal levels of functional dystrophin is a promising approach, but clinical trials are still in progress. Currently, supportive therapy and rehabilitation are the cornerstones of BMD treatment.

Pharmacological Therapy of Muscle Dystrophy

There is no approved BMD treatment to date. However, the management approach to this condition is often similar to that for milder DMD cases. Corticosteroids have been the mainstay of treatment for patients with significant muscle weakness. Prednisolone at a dose of 0.75 mg/kg/day or deflazacort at a dose of 0.9 mg/kg/day may be given initially.[26][27]

Corticosteroids should be started before physical disability develops and must continue even after losing ambulation. Glucocorticoid treatment helps prolong survival by delaying the onset of cardiomyopathy, improving pulmonary function, retarding scoliosis, and reducing the need for spinal surgery.[28][29] The steroid dose should be reduced by 25% to 33% if adverse effects develop. Nitric oxide is occasionally prescribed to improve muscular circulation.(A1)

Dilated cardiomyopathy with heart failure is a common cause of morbidity and mortality in patients with BMD. Early cardiac evaluation and treatment are thus vital. Angiotensin-converting enzyme inhibitors with or without β-blockers are the main treatments for patients with BMD who have developed cardiac complications.[30]


Rehabilitative care helps preserve muscle and overall function for as long as possible. An interprofessional approach addresses various aspects of this part of BMD management. Combining physical, speech, recreational, and occupational therapy is the best way to optimize patient outcomes. 

Surgical Management

Muscle weakness may produce progressive scoliosis and joint contractures in patients with BMD, though less frequently than in people with DMD. Monitoring and physical rehabilitation may benefit individuals with slowly evolving symptoms. Surgery may be considered in patients experiencing rapid symptom progression to help maintain ambulation for a longer period.

Combined Therapy

Individuals with severe respiratory failure may be managed with tracheostomy and assisted ventilation. Angiotensin-converting enzyme inhibitors and β-blockers may be given for associated cardiomyopathy. Home mechanical ventilation may reduce pulmonary pressure and protect the heart in patients with BMD when combined with cardioprotective medical therapy.[31][44]

Endocrine Management

Some children may experience impaired growth and delayed puberty. An endocrinology consultation may benefit these individuals. Low-dose testosterone can help promote normal bone development and prevent osteoporosis in boys with BMD.

Evolving Treatments

Previous clinical trials have shown no clear benefit from metformin treatment with or without L-citrulline.[32] Meanwhile, the synthetic glucocorticoid-like drug vamorolone has demonstrated potent anti-inflammatory activity through nuclear factor inhibition, improving sarcolemmal stability. This agent has shown early positive trial results. More randomized controlled trials are being conducted to find support for vamorolone's use in BMD management.[33](A1)

Differential Diagnosis

BMD has to be distinguished from other myopathies with muscle weakness as presenting symptoms, which include the following:

  • DMD: more severe and earlier onset than BMD. The patient becomes wheelchair-bound earlier, and the length of survival is shorter. Patients usually have much lower dystrophin concentrations.[34]
  • Polymyositis: an idiopathic inflammatory myopathy characterized by bilateral proximal muscle weakness. However, unlike BMD, polymyositis is not associated with distal pseudohypertrophy.[35]
  • Spinal muscular atrophy: an autosomal-recessive inherited disorder commonly presenting with hyporeflexia, tongue fasciculations, and weakness in the bulbar or brainstem muscles. Cognitive impairment is less frequent. Consider spinal muscular atrophy as an alternative diagnosis in the absence of dystrophin gene mutation.[36]
  • Limb-girdle muscular dystrophy: symptoms are similar to BMD, though calf muscle pseudohypertrophy is absent.[37]
  • Dilated cardiomyopathy: can arise from a mechanism other than muscular dystrophy.[38]
  • Emery-Dreyfuss muscular dystrophy: early contractures and cardiac defects help to distinguish this condition from BMD. Humeroperoneal muscle weakness and wasting begin in the 1st and 2nd decades of life.[39]
  • Myasthenia gravis: fluctuating skeletal muscle weakness can be the initial or only symptom of this condition, which can make it difficult to distinguish clinically from BMD. However, facial weakness, ptosis, and diplopia commonly occur in myasthenia gravis but not in BMD.[40]
  • Metabolic myopathies: mitochondrial disorders and glycogen and lipid storage diseases may manifest with generalized muscle weakness. However, many patients with these conditions develop symptoms as early as infancy. Hepatomegaly, hypotonia, and hypoglycemia are also common. Patients who reach adolescence or adulthood may experience exercise-induced muscle fatigue.[41]

A thorough clinical evaluation and the appropriate diagnostic exams can help distinguish these conditions from BMD.


BMD generally has a milder clinical course than DMD. However, the chances of survival decrease with time as the disease progresses. Patients become dependent on supportive interventions to prolong life. The average life expectancy of individuals with BMD is about 40 to 50 years. Death is most commonly due to dilated cardiomyopathy.[42]


BMD's potential complications include the following:

  • Loss of ambulation
  • Cognitive dysfunction
  • Growth impairment
  • Fractures
  • Cardiomyopathy
  • Joint contractures
  • Scoliosis
  • Postoperative chest infections
  • Progressive hepatic and pulmonary failure
  • Kidney failure from rhabdomyolysis and myoglobinuria
  • Adrenal insufficiency and immunosuppression from long-term corticosteroid use

Early intervention and comprehensive care can help manage symptoms and improve the quality of life for people affected by BMD.

Deterrence and Patient Education

Genetic counseling must be provided to families with a known dystrophin gene mutation. Female carriers should be educated about family planning options. Inheritance patterns must be clearly explained to patients and families to help them understand how BMD can be transmitted.

Late interventions do not benefit individuals with BMD. Therefore, patients and families should be educated about the disease process and encouraged to follow up regularly with their healthcare providers and rehabilitation specialists. Affected individuals must seek immediate treatment for new symptoms.

Patients and families must be informed of BMD treatment and diagnostic options. Information regarding the potential adverse effects of therapy, especially prolonged corticosteroid intake, must be provided before initiating treatments. Affected individuals and their families must be made aware of corticosteroid toxicity symptoms and advised to seek help immediately if such symptoms manifest. Patients should be provided with truthful expectations about disease outcomes.

Enhancing Healthcare Team Outcomes

The wide range of symptoms of BMD necessitates multidisciplinary care. Members of the interprofessional team include the following:

  • Primary care physicians or pediatricians: likely the first providers to clinically evaluate patients and render care. These professionals may initiate referrals to other providers and coordinate patient care needs.
  • Geneticists: oversee and interpret genetic test results and help formulate a personalized management plan for patients with BMD.
  • Genetic counselors: offer information and guidance regarding BMD's genetic aspects, including inheritance patterns and family planning options.
  • Nurses: administer treatments, reinforce patient education, and assist in coordinating patient care.
  • Rehabilitation team: comprised of physical, occupational, recreational, and speech therapists. The services provided by these professionals are critical to prolonging survival and improving the quality of life for patients affected by BMD.
  • Mental health professionals: provide emotional support, counseling, and coping strategies for patients and families affected by BMD.
  • Radiologists: interpret imaging tests necessary for evaluating cardiorespiratory symptoms, monitoring musculoskeletal changes, and management planning.
  • Cardiologists: monitor cardiac health and screen for cardiomyopathy. These providers oversee cardiac assessments and may recommend interventions to manage cardiac complications.
  • Pulmonologists and respiratory therapists: evaluate and manage respiratory function, addressing breathing difficulty or respiratory muscle weakness that may occur in individuals with BMD.
  • Intensivists: evaluate and treat patients with BMD in the intensive care setting.
  • Orthopedic surgeons: manage orthopedic complications like scoliosis and joint contractures that may arise due to progressive muscle weakness.
  • Nutritionists: address specific dietary needs and guide patients with BMD on maintaining proper nutrition and weight management.
  • Pharmacists: ensure that patients on glucocorticoids have the right dose and are aware of these drugs' possible side effects.
  • Neurologists: help in managing BMD's potential neurological complications.
  • Endocrinologists: render care to patients with BMD who experience delayed puberty.

Smooth coordination between health professionals is essential to improving clinical outcomes for patients with BMD.



Worton R. Muscular dystrophies: diseases of the dystrophin-glycoprotein complex. Science (New York, N.Y.). 1995 Nov 3:270(5237):755-6     [PubMed PMID: 7481760]


Ervasti JM, Ohlendieck K, Kahl SD, Gaver MG, Campbell KP. Deficiency of a glycoprotein component of the dystrophin complex in dystrophic muscle. Nature. 1990 May 24:345(6273):315-9     [PubMed PMID: 2188135]

Level 3 (low-level) evidence


Bushby KM, Gardner-Medwin D. The clinical, genetic and dystrophin characteristics of Becker muscular dystrophy. I. Natural history. Journal of neurology. 1993 Feb:240(2):98-104     [PubMed PMID: 8437027]


Bellayou H, Hamzi K, Rafai MA, Karkouri M, Slassi I, Azeddoug H, Nadifi S. Duchenne and Becker muscular dystrophy: contribution of a molecular and immunohistochemical analysis in diagnosis in Morocco. Journal of biomedicine & biotechnology. 2009:2009():325210. doi: 10.1155/2009/325210. Epub 2009 May 19     [PubMed PMID: 19461958]


Straub V, Guglieri M. An update on Becker muscular dystrophy. Current opinion in neurology. 2023 Oct 1:36(5):450-454. doi: 10.1097/WCO.0000000000001191. Epub 2023 Aug 21     [PubMed PMID: 37591308]

Level 3 (low-level) evidence


Flanigan KM. Duchenne and Becker muscular dystrophies. Neurologic clinics. 2014 Aug:32(3):671-88, viii. doi: 10.1016/j.ncl.2014.05.002. Epub     [PubMed PMID: 25037084]


Hegde MR, Chin EL, Mulle JG, Okou DT, Warren ST, Zwick ME. Microarray-based mutation detection in the dystrophin gene. Human mutation. 2008 Sep:29(9):1091-9. doi: 10.1002/humu.20831. Epub     [PubMed PMID: 18663755]


Takeshima Y, Yagi M, Okizuka Y, Awano H, Zhang Z, Yamauchi Y, Nishio H, Matsuo M. Mutation spectrum of the dystrophin gene in 442 Duchenne/Becker muscular dystrophy cases from one Japanese referral center. Journal of human genetics. 2010 Jun:55(6):379-88. doi: 10.1038/jhg.2010.49. Epub 2010 May 20     [PubMed PMID: 20485447]

Level 3 (low-level) evidence


Hoffman EP, Fischbeck KH, Brown RH, Johnson M, Medori R, Loike JD, Harris JB, Waterston R, Brooke M, Specht L. Characterization of dystrophin in muscle-biopsy specimens from patients with Duchenne's or Becker's muscular dystrophy. The New England journal of medicine. 1988 May 26:318(21):1363-8     [PubMed PMID: 3285207]

Level 3 (low-level) evidence


Romitti PA, Zhu Y, Puzhankara S, James KA, Nabukera SK, Zamba GK, Ciafaloni E, Cunniff C, Druschel CM, Mathews KD, Matthews DJ, Meaney FJ, Andrews JG, Conway KM, Fox DJ, Street N, Adams MM, Bolen J, MD STARnet. Prevalence of Duchenne and Becker muscular dystrophies in the United States. Pediatrics. 2015 Mar:135(3):513-21. doi: 10.1542/peds.2014-2044. Epub 2015 Feb 16     [PubMed PMID: 25687144]

Level 2 (mid-level) evidence


Lin J, Li H, Liao Z, Wang L, Zhang C. Comparison of Carrier and de novo Pathogenic Variants in a Chinese DMD/BMD Cohort. Frontiers in neurology. 2021:12():714677. doi: 10.3389/fneur.2021.714677. Epub 2021 Aug 5     [PubMed PMID: 34421809]


Aartsma-Rus A, Van Deutekom JC, Fokkema IF, Van Ommen GJ, Den Dunnen JT. Entries in the Leiden Duchenne muscular dystrophy mutation database: an overview of mutation types and paradoxical cases that confirm the reading-frame rule. Muscle & nerve. 2006 Aug:34(2):135-44     [PubMed PMID: 16770791]

Level 3 (low-level) evidence


Fong PY, Turner PR, Denetclaw WF, Steinhardt RA. Increased activity of calcium leak channels in myotubes of Duchenne human and mdx mouse origin. Science (New York, N.Y.). 1990 Nov 2:250(4981):673-6     [PubMed PMID: 2173137]

Level 3 (low-level) evidence


Bellinger AM, Reiken S, Carlson C, Mongillo M, Liu X, Rothman L, Matecki S, Lacampagne A, Marks AR. Hypernitrosylated ryanodine receptor calcium release channels are leaky in dystrophic muscle. Nature medicine. 2009 Mar:15(3):325-30. doi: 10.1038/nm.1916. Epub 2009 Feb 8     [PubMed PMID: 19198614]

Level 3 (low-level) evidence


Tidball JG, Villalta SA. NO may prompt calcium leakage in dystrophic muscle. Nature medicine. 2009 Mar:15(3):243-4. doi: 10.1038/nm0309-243. Epub     [PubMed PMID: 19265820]


Sander M, Chavoshan B, Harris SA, Iannaccone ST, Stull JT, Thomas GD, Victor RG. Functional muscle ischemia in neuronal nitric oxide synthase-deficient skeletal muscle of children with Duchenne muscular dystrophy. Proceedings of the National Academy of Sciences of the United States of America. 2000 Dec 5:97(25):13818-23     [PubMed PMID: 11087833]

Level 2 (mid-level) evidence


Lai Y, Thomas GD, Yue Y, Yang HT, Li D, Long C, Judge L, Bostick B, Chamberlain JS, Terjung RL, Duan D. Dystrophins carrying spectrin-like repeats 16 and 17 anchor nNOS to the sarcolemma and enhance exercise performance in a mouse model of muscular dystrophy. The Journal of clinical investigation. 2009 Mar:119(3):624-35. doi: 10.1172/JCI36612. Epub 2009 Feb 23     [PubMed PMID: 19229108]

Level 3 (low-level) evidence


Kaido M, Arahata K, Hoffman EP, Nonaka I, Sugita H. Muscle histology in Becker muscular dystrophy. Muscle & nerve. 1991 Nov:14(11):1067-73     [PubMed PMID: 1745279]


Bell CD, Conen PE. Histopathological changes in Duchenne muscular dystrophy. Journal of the neurological sciences. 1968 Nov-Dec:7(3):529-44     [PubMed PMID: 5709861]


Birnkrant DJ, Bushby K, Bann CM, Apkon SD, Blackwell A, Brumbaugh D, Case LE, Clemens PR, Hadjiyannakis S, Pandya S, Street N, Tomezsko J, Wagner KR, Ward LM, Weber DR, DMD Care Considerations Working Group. Diagnosis and management of Duchenne muscular dystrophy, part 1: diagnosis, and neuromuscular, rehabilitation, endocrine, and gastrointestinal and nutritional management. The Lancet. Neurology. 2018 Mar:17(3):251-267. doi: 10.1016/S1474-4422(18)30024-3. Epub 2018 Feb 3     [PubMed PMID: 29395989]

Level 3 (low-level) evidence


Shrestha S, Munakomi S. Gower Sign. StatPearls. 2024 Jan:():     [PubMed PMID: 31082017]


Gatta V, Scarciolla O, Gaspari AR, Palka C, De Angelis MV, Di Muzio A, Guanciali-Franchi P, Calabrese G, Uncini A, Stuppia L. Identification of deletions and duplications of the DMD gene in affected males and carrier females by multiple ligation probe amplification (MLPA). Human genetics. 2005 Jun:117(1):92-8     [PubMed PMID: 15841391]


Hwa HL, Chang YY, Chen CH, Kao YS, Jong YJ, Chao MC, Ko TM. Multiplex ligation-dependent probe amplification identification of deletions and duplications of the Duchenne muscular dystrophy gene in Taiwanese subjects. Journal of the Formosan Medical Association = Taiwan yi zhi. 2007 May:106(5):339-46     [PubMed PMID: 17561468]

Level 2 (mid-level) evidence


Leung DG. Magnetic resonance imaging patterns of muscle involvement in genetic muscle diseases: a systematic review. Journal of neurology. 2017 Jul:264(7):1320-1333. doi: 10.1007/s00415-016-8350-6. Epub 2016 Nov 25     [PubMed PMID: 27888415]

Level 1 (high-level) evidence


Hoffman EP, Kunkel LM, Angelini C, Clarke A, Johnson M, Harris JB. Improved diagnosis of Becker muscular dystrophy by dystrophin testing. Neurology. 1989 Aug:39(8):1011-7     [PubMed PMID: 2668783]


Ryder S, Leadley RM, Armstrong N, Westwood M, de Kock S, Butt T, Jain M, Kleijnen J. The burden, epidemiology, costs and treatment for Duchenne muscular dystrophy: an evidence review. Orphanet journal of rare diseases. 2017 Apr 26:12(1):79. doi: 10.1186/s13023-017-0631-3. Epub 2017 Apr 26     [PubMed PMID: 28446219]


Yiu EM, Kornberg AJ. Duchenne muscular dystrophy. Journal of paediatrics and child health. 2015 Aug:51(8):759-64. doi: 10.1111/jpc.12868. Epub 2015 Mar 9     [PubMed PMID: 25752877]


Gloss D, Moxley RT 3rd, Ashwal S, Oskoui M. Practice guideline update summary: Corticosteroid treatment of Duchenne muscular dystrophy: Report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2016 Feb 2:86(5):465-72. doi: 10.1212/WNL.0000000000002337. Epub     [PubMed PMID: 26833937]

Level 1 (high-level) evidence


Biggar WD, Harris VA, Eliasoph L, Alman B. Long-term benefits of deflazacort treatment for boys with Duchenne muscular dystrophy in their second decade. Neuromuscular disorders : NMD. 2006 Apr:16(4):249-55     [PubMed PMID: 16545568]

Level 2 (mid-level) evidence


Politano L, Nigro G. Treatment of dystrophinopathic cardiomyopathy: review of the literature and personal results. Acta myologica : myopathies and cardiomyopathies : official journal of the Mediterranean Society of Myology. 2012 May:31(1):24-30     [PubMed PMID: 22655514]


Emery AE. The muscular dystrophies. Lancet (London, England). 2002 Feb 23:359(9307):687-95     [PubMed PMID: 11879882]


Hanff E, Hafner P, Bollenbach A, Bonati U, Kayacelebi AA, Fischer D, Tsikas D. Effects of single and combined metformin and L-citrulline supplementation on L-arginine-related pathways in Becker muscular dystrophy patients: possible biochemical and clinical implications. Amino acids. 2018 Oct:50(10):1391-1406. doi: 10.1007/s00726-018-2614-7. Epub 2018 Jul 12     [PubMed PMID: 30003335]


Elhalag RH, Motawea KR, Talat NE, Rouzan SS, Shah J. Efficacy of vamorolone in treatment of Duchene muscle dystrophy. A meta-analysis. Frontiers in neurology. 2023:14():1107474. doi: 10.3389/fneur.2023.1107474. Epub 2023 Feb 1     [PubMed PMID: 36816559]

Level 1 (high-level) evidence


Alvarez Leal M, Hernández Sifuentes PM, Pérez-Zuno JA. [Differential diagnosis of Becker and Duchenne muscular dystrophy]. Gaceta medica de Mexico. 1994 Nov-Dec:130(6):454-8     [PubMed PMID: 7557060]


Furuya T, Tateishi M, Hara M, Kashiwazaki S, Takeuchi M. [Differential diagnosis of Becker-type muscular dystrophy from polymyositis]. Nihon Naika Gakkai zasshi. The Journal of the Japanese Society of Internal Medicine. 1996 Jun 10:85(6):927-9     [PubMed PMID: 8753060]

Level 3 (low-level) evidence


Lunt PW, Cumming WJ, Kingston H, Read AP, Mountford RC, Mahon M, Harris R. DNA probes in differential diagnosis of Becker muscular dystrophy and spinal muscular atrophy. Lancet (London, England). 1989 Jan 7:1(8628):46-7     [PubMed PMID: 2563028]

Level 3 (low-level) evidence


Norman A, Thomas N, Coakley J, Harper P. Distinction of Becker from limb-girdle muscular dystrophy by means of dystrophin cDNA probes. Lancet (London, England). 1989 Mar 4:1(8636):466-8     [PubMed PMID: 2563842]


Dec GW, Fuster V. Idiopathic dilated cardiomyopathy. The New England journal of medicine. 1994 Dec 8:331(23):1564-75     [PubMed PMID: 7969328]


Puckelwartz M, McNally EM. Emery-Dreifuss muscular dystrophy. Handbook of clinical neurology. 2011:101():155-66. doi: 10.1016/B978-0-08-045031-5.00012-8. Epub     [PubMed PMID: 21496632]


Vincent A, Palace J, Hilton-Jones D. Myasthenia gravis. Lancet (London, England). 2001 Jun 30:357(9274):2122-8     [PubMed PMID: 11445126]


Tarnopolsky MA. Metabolic Myopathies. Continuum (Minneapolis, Minn.). 2016 Dec:22(6, Muscle and Neuromuscular Junction Disorders):1829-1851     [PubMed PMID: 27922496]


Cox GF, Kunkel LM. Dystrophies and heart disease. Current opinion in cardiology. 1997 May:12(3):329-43     [PubMed PMID: 9243091]

Level 3 (low-level) evidence