Duchenne's Muscular Dystrophy

Department of Pharmacy
Pokhara University
School of Health and Allied Sciences
Pokhara University
Duchenne's Muscular
Dystrophy
Atul Adhikari
Third Semester, B. Pharm.
Pokhara University, Dhungepatan,
Lekhnath-12, Kaski , Nepal

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Pokhara University
Contents
1. Introduction
2. Causes
3. Dystrophin
4. Inheritance
5. Symptom
6. Treatment
7. Complications and Treatment
8. Conclusion
9. References

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Pokhara University
Introduction
•Duchenne's muscular dystrophy (DMD) is a genetic
condition which affects the muscles, causing muscle
weakness and can be inherited.
•It is a serious condition which starts in early childhood.
•It usually effects only boys, although girls may carry the
Duchene gene.

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Pokhara University
• The muscle weakness is mainly in the 'proximal'
muscles, which are those near the trunk of the body,
around the hips and the shoulders.
• This means that fine movements, such as those using
the hands and fingers, are less affected than
movements like walking.
• It starts in childhood and may be noticed when a child
has difficulty standing up, climbing or running.
4Duchenne's Muscular Dystrophy

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Pokhara University
Causes
• The cause is a genetic change.
• Muscles contain a protein (chemical) called
dystrophin, which is necessary for muscles to
function properly.
• People with DMD have a shortage of dystrophin in
their muscles. The lack of dystrophin leads to muscle
fibre damage and a gradual weakening of the
muscles. The shortage of dystrophin is caused by a
faulty gene.

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Pokhara University
Dystrophin
• Dystrophin is a rod-shaped cytoplasmic protein, and a
vital part of a protein complex that connects the
cytoskeleton of a muscle fiber to the surrounding
extracellular matrix through the cell membrane. This
complex is variously known as the costamere or the
dystrophin-associated protein complex.
• Many muscle proteins, such as α-dystrobrevin, syncoilin,
synemin, sarcoglycan, dystroglycan, and sarcospan,
colocalize with dystrophin at the costamere.
• The Dystrophin gene is the longest human gene known on
DNA level,

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Pokhara University

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Pokhara University
Inheritance
• DMD is inherited in a pattern called 'X-linked inheritance
• Boys have one X chromosome and one Y chromosome; girls
have two X chromosomes.
• The DMD gene is 'carried' by women, but does not usually
cause problems in girls or women
• This is because of there being two X chromosomes in women:
one X chromosome has the 'faulty' DMD gene, and the other X
chromosome has a normal gene, which compensates for the
faulty one.

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Pokhara University
• Boys with the DMD gene do not have a second X
chromosome and so they cannot compensate for the
faulty gene. Therefore, boys with the DMD gene
always have symptoms of the disease

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Pokhara University

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Pokhara University
• For a woman who carries the DMD gene, there is a 1
in 2 chance that her sons will have DMD, and a 1 in 2
chance that her daughters will carry the gene.

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Pokhara University
Symptoms
• The muscle weakness is not noticeable at birth, even
though the child is born with the gene which causes
it.
• The weakness develops gradually. It usually shows up
in early childhood.
• Symptoms are mild at first, but increase as the child
gets older.

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Pokhara University
• The symptoms usually start around age 1-3 years.
Parents may notice:
• Difficulty with walking, running, jumping and
climbing stairs. Walking may look different with a
'waddling' type of walk. The boy may be late in
starting to walk (although many children without
DMD also walk late).
• When you pick the child up, you may feel as if he
'slips through your hands', due to looseness of the
muscles around the shoulder.
• The calf muscles may look bulky, although they are
not strong.

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Pokhara University
• As he gets older, the child may use his hands to help
him get up, looking as if he is 'climbing up his legs'.
This is called 'Gower's sign'.
• Some boys with DMD also have a learning difficulty.
Usually this is not severe.
• Sometimes, a delay in development may be the first
sign of DMD. The child's speech development may
also be delayed.

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Pokhara University

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Pokhara University
Diagnosis
• Diagnosis may be suspected because of the child's
symptoms .
• When looking for signs of DMD, it is important to watch
the child running and getting up from the floor - the
muscle weakness is more noticeable during these
activities.

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Pokhara University
• The first step in making the diagnosis is a blood test.
This tests for creatine kinase.
• Children with DMD always have a very high level of
creatine kinase (about 10-100 times normal).
• If the creatine kinase level is high, further tests are
needed to see whether this is due to DMD or to some
other condition.
• The next step in diagnosing DMD involves either a
muscle biopsy and/or genetic tests:

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Pokhara University
• A muscle biopsy involves taking a small sample of a
muscle, under local anaesthetic. The sample is
examined under a microscope using special
techniques to look at the muscle fibres and the
dystrophin protein.
• Genetic tests are done using a blood sample. The
DNA in the blood is tested to look at the dystrophin
gene. This test can diagnose most cases of DMD.

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Pokhara University
Treatment
• There is no cure for DMD at present. However,
treatments can help according to complications
observed.
• support may be needed for the legs and ankles and
wheelchairs for late stages.
• Treatment with medication called 'corticosteroids'
(or 'steroids') can help to maintain the child's muscle
strength such as prednisolone or deflazacort.

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Pokhara University
• Child will need regular check-ups. This may involve
different specialists, for example, heart and lung
checks, orthopaedic care for bones and joints,
physiotherapists, and dieticians.

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Pokhara University
Complications of Duchenne's muscular
dystrophy and treatment
• Anesthetics
People with DMD need extra care if they have a
general anesthetic. Certain anesthetic medicines can
cause a harmful reaction for people who have DMD.
Also, extra care for the chest and breathing is needed.

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Pokhara University
• Osteoporosis
• People with DMD may develop osteoporosis
(thinning of the bones).
• This is due to lack of mobility and also to steroid
treatment.
• A good intake of vitamin D and calcium helps keep
bones strong. These can be obtained from certain
foods or from vitamin supplements, and by action of
sunshine on the skin (which makes natural vitamin
D).

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Pokhara University
• Joint and spinal complications
• Muscle weakness can result in some joints becoming
tight - this is called a 'contracture'. This can be treated
using orthotic devices (splints or casts).
• Curvature of the spine (scoliosis) can occur due to
muscle weakness. The scoliosis can cause discomfort
and is not helpful for posture and breathing.
Treatments which can help are a spinal brace, or
surgery to the spine.

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Pokhara University
• Nutrition and digestion
• Some children with DMD are prone to being
overweight, especially if taking steroid treatment.
Teenagers and adults with DMD may be underweight,
due to loss of muscle bulk. Dietary advice can be
helpful in these situations.
• Constipation can be a symptom for anyone who is not
mobile. This can be treated with laxatives and a high
fiber diet.

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Pokhara University
• In the later stages of DMD , people with DMD may have
difficulty with chewing and swallowing food. They may
need a careful assessment and nutritional advice or
supplements. If the problem is severe, then a 'gastrostomy'
(a feeding tube into the stomach) may be needed.
• Chest and breathing complications
• the breathing muscles weaken, causing shallow breathing
and a less effective cough mechanism. This can lead to chest
infections, because mucus and bacteria are not cleared so
easily from the chest.

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Pokhara University
• getting medical advice early and taking antibiotics where
needed. Also, you will be offered immunization with
influenza and pneumococcal vaccines, to help prevent
chest infections. Physiotherapy can help to clear mucus
from the chest.
• Cardiac (heart) complications
• Teenagers and adults with DMD may develop a heart
problem called cardiomyopathy, which means weakness of
the heart muscle
• Cardiomyopathy can be helped by medication.

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Pokhara University
Conclusion
• DMD is a very serious condition in which the muscle
weakness increases gradually over the years,
complications eventually develop and it shorten life.
• The breathing or heart problems usually become
more serious for older teenagers or people in their
twenties and is major cause of death.
• At present, average life expectancy for people with
DMD is 27 years

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Pokhara University
THANK YOUU
AND
HAVE A GOOD DAY

Duchenne's Muscular Dystrophy

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