History

A typical developmental history of a patient with BMD may include the following:

Delayed gross motor milestones (eg, late walking, running, jumping, difficulty with stair climbing) may be reported.
Initially, some children who are later diagnosed with BMD may be called clumsy.
Increasing numbers of falls, toe walking, and difficulty rising from the floor may be later features.
Proximal muscle weakness is reported.
Subclinical cases may manifest later in life; dilated cardiomyopathy can be the first sign of BMD.
Elbow contractures may be seen later in life.

Physical

See the list below:

The Gowers sign is not a specific finding for muscular dystrophy, but it does point to proximal weakness in the hip extensors, leading to the pattern of movement seen when patients rise from the floor.
A weakness pattern limited to specific muscle groups may help to differentiate BMD from other muscular dystrophies (such as limb-girdle and Emery-Dreifuss muscular dystrophies).
Progressive, symmetrical muscle weakness and atrophy with pseudohypertrophic calves may be seen.
Cases have been described of patients presenting without weakness but with symptoms of cardiomyopathy or cramps as the only indication of a myopathic process. Isolated weakness to the quadriceps femoris may be the only symptom noted.
Fasciculation or sensory modality abnormalities can exclude the diagnosis of a dystrophinopathy.
Preservation of neck flexor muscle strength may differentiate BMD from DMD.

Causes

BMD is an X-linked, recessive, inherited disorder. A family history of similarly affected maternal uncles assists the clinician in confirming a diagnosis of BMD.

A woman is an obligate heterozygote if she has an affected son and one other affected relative in the maternal line.
A woman with more than 1 affected child and no family history in the maternal line may have a germline mutation or a germline mosaicism.
An isolated proband without a family history may be explained by a mutation occurring in the egg at or following conception in which only some cells were affected (mosaicism). On the other hand, the proband's mother may have inherited the gene mutation if (1) her mother was a carrier or (2) her mother or father had somatic or germline mosaicism.
Siblings of the proband are at risk of transmitting the gene defect based on the carrier status of the mother.
- A carrier mother has a 50% transmission rate for the mutation, per pregnancy; daughters inheriting the mutation will be carriers, and sons with the mutation will be affected.
- Mothers with germline and/or somatic mosaicism have a higher risk of transmitting the mutation.

Differential Diagnoses

Becker PE, Kiener F. [A new x-chromosomal muscular dystrophy.]. Arch Psychiatr Nervenkr Z Gesamte Neurol Psychiatr. 1955. 193(4):427-48. [QxMD MEDLINE Link].
Becker PE. Two families of benign sex-linked recessive muscular dystrophy. Rev Can Biol. 1962 Sep-Dec. 21:551-66. [QxMD MEDLINE Link].
Andrews JG, Wahl RA. Duchenne and Becker muscular dystrophy in adolescents: current perspectives. Adolesc Health Med Ther. 2018. 9:53-63. [QxMD MEDLINE Link]. [Full Text].
Thada PK, Bhandari J, Umapathi KK. Becker Muscular Dystrophy. StatPearls. 2023 Jul 19. [QxMD MEDLINE Link]. [Full Text].
Straub V, Guglieri M. An update on Becker muscular dystrophy. Curr Opin Neurol. 2023 Oct 1. 36 (5):450-4. [QxMD MEDLINE Link]. [Full Text].
Angelini C, Fanin M, Pegoraro E, et al. Clinical-molecular correlation in 104 mild X-linked muscular dystrophy patients: characterization of sub-clinical phenotypes. Neuromuscul Disord. 1994 Jul. 4(4):349-58. [QxMD MEDLINE Link].
Gurvich OL, Tuohy TM, Howard MT, et al. DMD pseudoexon mutations: splicing efficiency, phenotype, and potential therapy. Ann Neurol. 2008 Jan. 63(1):81-9. [QxMD MEDLINE Link].
Ashton EJ, Yau SC, Deans ZC, et al. Simultaneous mutation scanning for gross deletions, duplications and point mutations in the DMD gene. Eur J Hum Genet. 2008 Jan. 16(1):53-61. [QxMD MEDLINE Link].
Arahata K, Beggs AH, Honda H, et al. Preservation of the C-terminus of dystrophin molecule in the skeletal muscle from Becker muscular dystrophy. J Neurol Sci. 1991 Feb. 101(2):148-56. [QxMD MEDLINE Link].
Koenig M, Beggs AH, Moyer M, et al. The molecular basis for Duchenne versus Becker muscular dystrophy: correlation of severity with type of deletion. Am J Hum Genet. 1989 Oct. 45(4):498-506. [QxMD MEDLINE Link]. [Full Text].
Schwartz M, Hertz JM, Sveen ML, et al. LGMD2I presenting with a characteristic Duchenne or Becker muscular dystrophy phenotype. Neurology. 2005 May 10. 64(9):1635-7. [QxMD MEDLINE Link].
Cirak S, Feng L, Anthony K, Arechavala-Gomeza V, Torelli S, Sewry C, et al. Restoration of the Dystrophin-associated Glycoprotein Complex After Exon Skipping Therapy in Duchenne Muscular Dystrophy. Mol Ther. 2011 Nov 15. [QxMD MEDLINE Link].
Mavrogeni S, Markousis-Mavrogenis G, Papavasiliou A, Kolovou G. Cardiac involvement in Duchenne and Becker muscular dystrophy. World J Cardiol. 2015 Jul 26. 7 (7):410-4. [QxMD MEDLINE Link].
Nicolas A, Raguenes-Nicol C, Ben Yaou R, et al. Becker muscular dystrophy severity is linked to the structure of dystrophin. Hum Mol Genet. 2015 Mar 1. 24 (5):1267-79. [QxMD MEDLINE Link].
Cardiovascular health supervision for individuals affected by Duchenne or Becker muscular dystrophy. Pediatrics. 2005 Dec. 116(6):1569-73. [QxMD MEDLINE Link]. [Full Text].
Emery AE, Skinner R. Clinical studies in benign (Becker type) X-linked muscular dystrophy. Clin Genet. 1976 Oct. 10(4):189-201. [QxMD MEDLINE Link].
Holloway SM, Wilcox DE, Wilcox A, et al. Life expectancy and death from cardiomyopathy amongst carriers of Duchenne and Becker muscular dystrophy in Scotland. Heart. 2007 Oct 11. [QxMD MEDLINE Link].
Young HK, Barton BA, Waisbren S, et al. Cognitive and Psychological Profile of Males With Becker Muscular Dystrophy. J Child Neurol. 2007 Dec 3. [QxMD MEDLINE Link].
De Wel B, Willaert S, Nadaj-Pakleza A, et al. Respiratory decline in adult patients with Becker muscular dystrophy: a longitudinal study. Neuromuscul Disord. 2020 Dec 26. [QxMD MEDLINE Link].
Zhang H, Zhu Y, Sun Y, et al. Serum creatinine level: a supplemental index to distinguish Duchenne muscular dystrophy from Becker muscular dystrophy. Dis Markers. 2015. 2015:141856. [QxMD MEDLINE Link].
Menezes MP, North KN. Inherited neuromuscular disorders: Pathway to diagnosis. J Paediatr Child Health. 2011 Nov 3. [QxMD MEDLINE Link].
Lim BC, Lee S, Shin JY, Kim JI, Hwang H, Kim KJ, et al. Genetic diagnosis of Duchenne and Becker muscular dystrophy using next-generation sequencing technology: comprehensive mutational search in a single platform. J Med Genet. 2011 Nov. 48(11):731-6. [QxMD MEDLINE Link].
Marty B, Gilles R, Toussaint M, et al. Comprehensive evaluation of structural and functional myocardial impairments in Becker muscular dystrophy using quantitative cardiac magnetic resonance imaging. Eur Heart J Cardiovasc Imaging. 2018 Dec 24. [QxMD MEDLINE Link].
Rutkove SB, Darras BT. Electrical impedance myography for the assessment of children with muscular dystrophy: a preliminary study. J Phys Conf Ser. 2013. 434(1):[QxMD MEDLINE Link]. [Full Text].
Magot A, Wahbi K, Leturcq F, et al. Diagnosis and management of Becker muscular dystrophy: the French guidelines. J Neurol. 2023 Oct. 270 (10):4763-81. [QxMD MEDLINE Link]. [Full Text].
Grootenhuis MA, de Boone J, van der Kooi AJ. Living with muscular dystrophy: health related quality of life consequences for children and adults. Health Qual Life Outcomes. 2007. 5:31. [QxMD MEDLINE Link]. [Full Text].
Yamada Y, Kawakami M, Wada A, Otsuka T, Muraoka K, Liu M. A comparison of swallowing dysfunction in Becker muscular dystrophy and Duchenne muscular dystrophy. Disabil Rehabil. 2017 Mar 13. 1-5. [QxMD MEDLINE Link].
Hayes J, Veyckemans F, Bissonnette B. Duchenne muscular dystrophy: an old anesthesia problem revisited. Paediatr Anaesth. 2008 Feb. 18(2):100-6. [QxMD MEDLINE Link].
Segura LG, Lorenz JD, Weingarten TN, Scavonetto F, Bojanic K, Selcen D, et al. Anesthesia and Duchenne or Becker muscular dystrophy: review of 117 anesthetic exposures. Paediatr Anaesth. 2013 Sep. 23(9):855-64. [QxMD MEDLINE Link].
Jenkins HM, Stocki A, Kriellaars D, Pasterkamp H. Breath stacking in children with neuromuscular disorders. Pediatr Pulmonol. 2013 Aug 16. [QxMD MEDLINE Link].
Pouwels S, de Boer A, Leufkens HG, Weber WE, Cooper C, van Onzenoort HA, et al. Risk of fracture in patients with muscular dystrophies. Osteoporos Int. 2013 Aug 15. [QxMD MEDLINE Link].
Duan D. Myodys, a full-length dystrophin plasmid vector for Duchenne and Becker muscular dystrophy gene therapy. Curr Opin Mol Ther. 2008 Feb. 10(1):86-94. [QxMD MEDLINE Link].
Bowles DE, McPhee SW, Li C, Gray SJ, Samulski JJ, Camp AS, et al. Phase 1 Gene Therapy for Duchenne Muscular Dystrophy Using a Translational Optimized AAV Vector. Mol Ther. 2011 Nov 8. [QxMD MEDLINE Link].