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Duchenne Muscular Dystrophy. BRIAN CHANDA CHILUBA Dip.PT; Cert. NDT NEUROLOGY CLASS PRESENTATION. Overview. Basic information about Duchenne muscular dystrophy Inheritance Prevalence Symptoms Treatments. What Is Duchenne Muscular Dystrophy? (1). Genetic Progressive muscle weakness - PowerPoint PPT Presentation
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DuchenneDuchenneMuscular Muscular DystrophyDystrophyBRIAN CHANDA CHILUBABRIAN CHANDA CHILUBA
Dip.PT; Cert. NDTDip.PT; Cert. NDT
NEUROLOGY CLASS NEUROLOGY CLASS PRESENTATIONPRESENTATION
OverviewOverview
Basic information about Duchenne Basic information about Duchenne muscular dystrophymuscular dystrophy
InheritanceInheritance PrevalencePrevalence SymptomsSymptoms TreatmentsTreatments
What Is Duchenne What Is Duchenne Muscular Dystrophy?Muscular Dystrophy?(1)(1)
GeneticGenetic
Progressive muscle weaknessProgressive muscle weakness
Defects in muscle proteinsDefects in muscle proteins
Death of muscle tissueDeath of muscle tissue
MUSCULAR DYSTROPHYMUSCULAR DYSTROPHYMuscular dystrophies - group of genetic conditions
characterized by progressive muscle weakness and wasting
(atrophy)
20 different types of muscular dystrophy exist
(DMD) is named after the French neurologist Guillaume
Benjamin Amand Duchenne (1806–1875), who first described the
disease in 1861
DMDDMD
(DMD) is a severe recessive X-linked form of muscular
dystrophy characterized by rapid progression of muscle
degeneration, eventually leading to loss of ambulation and
death
DMD is caused by a defective gene for dystrophin (a protein
in the muscles) or by mutations in the dystrophin gene, which is
located on the X chromosome
DMDDMD
DMD absence of the dystrophin protein weakens the
connections between all of the proteins in the muscle and the cell
membrane
cell membrane becomes weaker and ruptures
particles, such as calcium, can move in and out of the ruptured
cell membrane
Where is This Gene?Where is This Gene?
PHYSIOLOGY OF PHYSIOLOGY OF DYSTROPHINDYSTROPHIN
The dystrophin molecule anchors the cytoskeleton of muscle cells to the extracellular matrix, via the dystrophin glycoprotein complex.
This includes the sarcoglycans (mutations in which cause limb-girdle muscular dystrophies) and dystroglycans.
Muscle cells that lack dystrophin are mechanically fragile, and fail after a few years, hence progressive muscle weakness.
Duchenne Duchenne Muscular Muscular Dystrophy InheritanceDystrophy Inheritance(1)(1)
Mother carries the recessive gene Mother carries the recessive gene and passes it to her childand passes it to her child
TraitTrait is usually expressed in is usually expressed in
males onlymales only
Prevalence of DMDPrevalence of DMD(1)(1)
Affects one in Affects one in 3500 to 5000 3500 to 5000 newborn malesnewborn males
1/3 of these 1/3 of these with previous family previous family historyhistory
2/3 sporadic2/3 sporadic
Symptoms of DMDSymptoms of DMD(1)(1)
Symptoms usually appear before age 6 Symptoms usually appear before age 6 Delayed developmental milestonesDelayed developmental milestones
Loss of motor skillsLoss of motor skills
Characteristic gaitCharacteristic gait
Calf hypertrophyCalf hypertrophy
Clumsiness/frequent fallsClumsiness/frequent falls
More Symptoms of More Symptoms of DMDDMD(1)(1)
Muscle weaknessMuscle weakness
Difficulty climbing stairs or hillsDifficulty climbing stairs or hills
Difficulty rising (Gower’s sign)Difficulty rising (Gower’s sign)
Difficulty walking/runningDifficulty walking/running
GOWERS SIGNGOWERS SIGN
PROGNOSISPROGNOSIS
Duchenne muscular dystrophy leads to
quickly worsening disability. Death
usually occurs by age 25, typically from
lung disorders
Treatments for DMD Treatments for DMD (1)(1)
To improve breathing:To improve breathing: OO22 therapy therapy
VentilatorVentilator
Scoliosis surgeryScoliosis surgery
TracheotomyTracheotomy
Treatments (cont.) Treatments (cont.) (1)
To improve mobility:To improve mobility: Physical therapyPhysical therapy
Surgery on tight jointsSurgery on tight joints
Prednisone-pPrednisone-ppppppppppppppppppppppppppppppppppppppppp
Non-steroidal medications-Non-steroidal medications-oooooooooooo
WheelchairWheelchair
PHYSIOTHERAPY PHYSIOTHERAPY TREATMENTTREATMENT
AIM TO :
minimize the development of contractures and deformity by developing a program of stretches and exercises where appropriate
anticipate and minimize other secondary complications of a physical nature
monitor respiratory function and advise on techniques to assist with breathing exercises and methods of clearing secretions
The Beginning of Gene Therapy
for DMD (2)
Advances in Gene Advances in Gene TherapyTherapy(3)(3)
Researches have developed Researches have developed ""minigenes,minigenes," which carry instructions " which carry instructions for a slightly smaller version of for a slightly smaller version of dystrophin, that can fit inside a virusdystrophin, that can fit inside a virus
Researchers have also created the so-Researchers have also created the so-called called gutted virus,gutted virus, a virus that has had a virus that has had its own genes removed so that it is its own genes removed so that it is carrying only the dystrophin gene carrying only the dystrophin gene
Problems with Gene Problems with Gene TherapyTherapy(3)(3)
Muscle tissue is large and relatively Muscle tissue is large and relatively impenetrableimpenetrable
Viruses might provoke the immune Viruses might provoke the immune system and cause the destruction of system and cause the destruction of muscle fibers with the new genes muscle fibers with the new genes
COMPLICATIONSCOMPLICATIONS•Cardiomyopathy•Congestive heart failure (rare)•Deformities•Heart arrhythmias (rare)•Mental impairment (varies, usually minimal)•Permanent, progressive disability
Decreased mobilityDecreased ability to care for self
•Pneumonia or other respiratory infections•Respiratory failure
References:References:1. “Muscular Dystrophy” PowerPoint by Katherine Kolor, PhD, MS,
CDC Ambassador Program, June 2005.2. Pobojewski, S. The University Record, November 9, 1998. U-M’s
improved viral vector delivers dystrophin gene to mouse muscle without major immune Response [online]. 1998. [cited 2005 June 26]. Available at URL: http://www.umihc.edu/~urecord/9899/Nov09_98/12.html
3. Journey of Love: A Parent’s Guide to Duchenne Muscular Dystrophy [online]. 2004. [cited 2005 June 22]. Available from URL: http://www.mdausa.org/publications/journey/5.html
4. Dictionary.com. Lexico Publishing Group, LLC. [online]. 2005. [cited 2005 June 22]. Available from URL: http://dictionary.reference.com/
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