24/02/2023
DUCHENNE MUSCULAR DYSTROPHY
Muscular dystrophy (MD) is a genetically and clinically heterogeneous rare neuromuscular diseases that cause progressive weakness and breakdown of skeletal muscles over time.The disorders differ as to which muscles are primarily affected, the degree of weakness, how fast they worsen, and when symptoms begin. Some types are also associated with problems in other organs.
Over 30 different disorders are classified as muscular dystrophies including Duchenne muscular dystrophy. Duchenne muscular dystrophy (DMD) accounts for approximately 50% of cases and affects males beginning around the age of four. Other relatively common muscular dystrophies include Becker muscular dystrophy, facioscapulohumeral muscular dystrophy, and myotonic dystrophy, whereas limb–girdle muscular dystrophy and congenital muscular dystrophy are themselves groups of several,usually ultrarare genetic disorders.
This article is going to build on one of the commonest form of muscular dystrophy, which we now know to be Duchenne Muscular dystrophy.
DUCHENNE MUSCULAR DYSTROPHY
Duchenne muscular dystrophy (DMD) is a progressive form of muscular dystrophy that occurs primarily in males, though in rare cases may affect females. DMD causes progressive weakness and loss (atrophy) of skeletal and heart muscles. Early signs of DMD may include delayed ability to sit, stand, or walk and difficulties learning to speak. Muscle weakness is usually noticeable by 3 or 4 years of age and begins in the hips, pelvic area, upper legs, and shoulders. The calves may be enlarged. Children with DMD may have an unusual walk and difficulty running, climbing stairs, and getting up from the floor. DMD may also affect learning and memory, as well as communication and certain social emotional skills. Muscle weakness worsens with age and progresses to the arms, legs and trunk. Most children with DMD use a wheelchair full time by age 13. Heart and respiratory muscle problems begin in the teen years and lead to serious, life threatening complications.
DMD and Becker muscular dystrophy (BMD) are caused by changes (mutations) in the DMD gene. However, the presentation of BMD clearly shows diversity which creates a distinction. People with BMD have less severe symptoms than DMD. In addition, symptoms start later in childhood or in adolescence and progress more slowly.
The DMD gene codes for the protein dystrophin. Dystrophin is mainly made in skeletal and heart muscle cells, but a small amount is also made in nerve cells (neurons) in specific parts of the brain. DMD is inherited in an X-linked recessive pattern; however, it may also occur in people who do not have a family history of DMD. While there is no known cure for DMD, there are treatments that can help control symptoms. Due to the advancement of medical treatment, boys with DMD may now live into young adulthood.
Symptoms of Duchenne muscular dystrophy (DMD) are usually noticed in boys between 1 to 6 years of age.There is a steady decline in muscle strength between the ages of 6 and 11 years. By age 10, braces may be needed for walking. By age 13, most boys with DMD are using a wheelchair full-time. The signs and symptoms include:
•Taking longer to learn to sit, stand, or walk on own, which is known as delayed motor development. The average age for walking in boys with DMD is 18 months.
•Having a waddling walk and difficulty climbing stairs or running.
•Difficulty getting up from the floor. Children may walk their hands up their legs to stand which is known as the Gower maneuver.
•Enlarged calf muscles due to the calf muscle cells being replaced by fat and connective tissue (pseudohypertrophy). This may also cause calf pain.
•Muscle weakness first affecting the muscles of the hips, pelvic area, thighs and shoulders, and later the skeletal (voluntary) muscles in the arms, legs and trunk.
•Tight or rigid joints (also known as contractures) may develop as muscle loss progresses. If not treated, these will become severe, causing discomfort and restricting mobility and flexibility. Contractures can affect the knees, hips, feet, elbows, wrists and fingers.
•Scoliosis may develop within several years of full-time wheelchair use.
•By the early teens, the respiratory and heart muscles are also affected.
•Breathing problems due to weakness of the diaphragm and the other muscles around the lungs. Skeletal changes, such as scoliosis, may also increase breathing problems. Breathing problems may become life-threatening.
•Progressive enlargement of the heart (cardiomyopathy) that stops the heart from pumping blood efficiently, and becomes life-threatening in many cases.
Learning and memory issues (cognitive impairment) may occur in some cases, but do not worsen as DMD progresses.
Kindly return back later on to this page as I share in detailed manner, how the genetic mutation of DMD can result to the above mentioned condition. We’ll look at the inheritance aspect then finalize on the role of physiotherapy in DMD management.
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