Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy

ORPHA:98896
Epidemiology

The prevalence of DMD ranges between 1/3,500-1/ 9,300 male births. The prevalence of BMD varies from 1/16,700 to 1/18,500 male births. The prevalence of symptomatic female carriers is unknown.


Clinical description

Dystrophinopathies present with a spectrum of severity whereby BMD is at the mildest end and DMD the most severe, there is an intermediate phenotype in between. At the mildest end of the spectrum exercise-induced muscle cramps and myoglobinuria may be the only feature while at the severe end, there may be complete loss of muscle function, cardiomyopathy and respiratory failure. DMD presents in early childhood, motor milestones are delayed. Brain involvement leads to cognitive impairment (affecting about a third of patients) and/or pervasive behavioral disorders such as ADHD, autism, anxiety and OCD. Muscle hypertrophy is evident, especially in the calf muscles. Progression is rapid, such that by the age of 5 there is likely to be a waddling gait and positive Gowers’ sign. In untreated boys, walking is lost by 13 years of age (mean 9.5 years). Following loss of ambulation, scoliosis, respiratory failure and cardiomyopathy develop. 


Genetic counseling

The pattern of inheritance is X-linked recessive. Genetic counselling of affected families is recommended and screening of women carriers in the family is important.

 

Diagnostic methods

The clinical diagnosis can be confirmed by several methods. Creatine Kinase (CK) is very raised. Molecular genetic analysis by MLPA (multiplex ligation-dependent probe amplification) will show a deletion in 60%; full gene sequencing is necessary to identify small deletions, duplications and nonsense mutations. Muscle biopsy for dystrophin analysis which is absent in DMD and reduced in BMD.

 

Video of a Doctor describing the main points of the RD: Symptoms, Diagnosis, Experimental therapies etc


Management and treatment

There is no known cure for this group of dystrophinopathies. In DMD, treatment with corticosteroids stabilizes motor function and delays loss of ambulation and respiratory failure by several years. Physiotherapy and orthotics delay the onset of joint contractures. Non-invasive ventilation (NIV) to treat respiratory failure prolongs life expectancy. Regular cardiac monitoring from diagnosis with early treatment using ACE (angiotensin-converting enzyme) inhibitors and beta blockers stabilizes cardiomyopathy. For XLDCM, cardiac transplantation is the treatment of choice.


Prognosis

Life expectancy is shortened by cardiac and respiratory involvement, but can be substantially improved with regular monitoring and pro-active management.

Useful links:

Relevant Publications: PubMed

Clinical Trials: NIH US National Library of Medicine

European Reference Network: EURO-NMD

Greek Centers of Expertise: Παίδων, Αγία Σοφία

Patient Organizations: MDA Hellas, World Duchenne Organization

The documents contained in this web site are presented for information purposes only. The material is in no way intended to replace professional medical care by a qualified specialist and should   not be used as a basis for diagnosis or treatment   

Expert reviewer(s):  Dr Marina Katsalouli , Pr Maria Papadopoulos Last update: December 2020

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