Overview

Duchenne muscular dystrophy (DMD) is a  rear genetic disorder characterized by progressive muscle degeneration and weakness due to the alterations of a protein called dystrophin that helps keep muscle cells intact. It predominantly affects males, Muscle weakness becomes increasingly noticeable between the ages of 3 and 5, and most patients use a wheelchair by the time they are 12. During adolescence, heart and breathing muscles weaken, leading to serious, life-threatening complications. Duchenne is caused by a change or mutation in the gene that encodes instructions for creating dystrophin, an essential protein for muscle strength. Dystrophin is a protein that plays a key structural role in muscle fiber function. In healthy muscle, dystrophin interacts with other proteins at the cell membrane to stabilize and protect the cell during regular activity involving muscle contraction and relaxation. Genetic testing can confirm the diagnosis and identify the disease-causing mutation in the dystrophin gene.

Individuals with Duchenne produce little or no dystrophin in their muscle.

Without dystrophin, normal activity causes excessive damage to muscle cells, and over time is replaced with fat and fibrotic tissue. DMD carriers are females who have a normal dystrophin gene on one X chromosome and an abnormal dystrophin gene on the other X chromosome. Most carriers of DMD do not themselves have signs and symptoms of the disease, but a minority do. Symptoms can range from mild skeletal muscle weakness or cardiac involvement to severe weakness or cardiac effects and can begin in childhood or adulthood. boys with DMD usually did not survive much beyond their teen years. Thanks to advances in cardiac and respiratory care, life expectancy is increasing and many young adults with DMD attend college, have careers, get married, and have children. Survival into the early 30s is becoming more common than before.DMD treatment requires multidisciplinary care to coordinate the multiple specialized assessments and interventions needed to maximize function and quality of life for patients. The use of available treatments can help to maintain comfort and function and prolong life. physicians can help create individualized care plans regarding all medical and assistive aspects DMD patients require.

Signs and Symptoms

DMD causes muscle weakness that worsens over time, so common symptoms include:

• Progressive muscle weakness and atrophy (loss of muscle bulk) that begins in your child’s legs and pelvis. It occurs less severely in their arms, neck and other areas of their body.
• Calf muscle hypertrophy (increase in muscle size).
• Difficulty climbing up stairs.
• Difficulty walking that gets worse over time.
• Frequent falls.
• Waddling gait (walk).
• Toe walking.
• Fatigue.

Other common symptoms of DMD include:

• Cardiomyopathy.
• Breathing difficulties and shortness of breath.
• Cognitive impairment and learning differences.
• Delayed speech and language development.
• Developmental delay.
• Scoliosis (spine curvature).
• Short stature (height).

Cause

Duchenne muscular dystrophy (DMD) is caused by a change (mutation) in the gene that gives instructions for a protein called dystrophin. Dystrophin is a critical part of the dystrophin-glycoprotein complex (DGC), which plays an important role as a structural unit of muscle.

In DMD, both dystrophin and DGC proteins are missing, which ultimately leads to the death (necrosis) of muscle cells. People with DMD have less than 5% of the normal quantity of dystrophin needed for healthy muscles.

As people with DMD age, their muscles can’t replace the dead cells with new ones, and connective and adipose (fat) tissue gradually replaces muscle fibers.

Duchenne muscular dystrophy has X-linked recessive inheritance, but about 30% of cases happen spontaneously without a family history of the condition.

X-linked means the gene responsible for DMD is located on the X chromosome, one of two sex chromosomes. Males have an X and Y chromosome, and females have two X chromosomes.

Genes, like chromosomes, usually come in pairs. Recessive means that when there are two copies of the responsible gene, both copies must have a disease-causing change (pathogenic variant or mutation) for a person to have the condition. Since males only have one X chromosome, if that chromosome has the genetic variant that causes DMD, they’ll have DMD

Diagnosis

If your child is experiencing symptoms of Duchenne muscular dystrophy (DMD), your child’s healthcare provider will likely perform a physical exam, neurological exam and muscle exam. They’ll ask detailed questions about your child’s symptoms and medical history.

If your child’s provider suspects that your child may have DMD, they’ll likely order the following tests:

• Creatine kinase blood test: Your muscles release creatine kinase when they’re damaged, so elevated levels may indicate DMD. Levels typically peak by age 2 and can be more than 10 to 20 times above the normal range.
• Genetic blood test: A genetic blood test that looks for a complete or near-complete absence of the dystrophin gene can confirm the diagnosis of DMD.
• Muscle biopsy: Your child’s provider may take a small sample of their muscle tissue from a muscle in their thigh or calf. A specialist will then look at the sample under a microscope to look for signs of DMD.
• Electrocardiogram (EKG): As DMD almost always affects your heart, your child’s provider will likely perform an EKG to look for characteristic signs of DMD and to check the health of your child’s heart.

Management and Treatment

There’s no cure for Duchene muscular dystrophy (DMD), so the main goal of treatment is to manage symptoms and improve quality of life.

Supportive therapies for DMD include:

• Corticosteroids: Corticosteroids, such as prednisolone and deflazacort, are beneficial for delaying muscle strength loss, improving lung function, delaying scoliosis, slowing the progression of cardiomyopathy (heart weakness) and prolonging survival.
• Medication to treat cardiomyopathy: Early treatment with ACE inhibitors and/or beta-blockers may slow the progression of cardiomyopathy and prevent the onset of heart failure.
• Physical therapy: The main goal of physical therapy for DMD is to prevent contractures (permanent tightening of your muscles, tendons and skin). This usually involves certain stretching exercises.
• Surgery to help treat scoliosis and contractures: Surgery to release contractures may be necessary for severe cases. Surgery to correct scoliosis may improve lung and breathing function.
• Exercise: Your child’s healthcare provider will likely recommend gentle exercise to avoid muscle atrophy due to a lack of use. This is usually a combination of swimming pool and recreation-based exercises.

Other supportive therapies for DMD include:

• Mobility aids, such as braces, canes and wheelchairs.
• Tracheostomy and assisted ventilation for respiratory failure.

With improvement in supportive care over the years, the life expectancy of DMD has significantly improved over the past few decades. so, If you’re concerned about the risk of passing on DMD or other genetic conditions before trying to have a biological child, talk to your healthcare provider about genetic counseling. In some situations, prenatal testing may be able to diagnose DMD in early pregnancy.

Conclusion:

Finally if your loved ones are planning for parenthood in late 30s we would suggest you genetic counselling , also you can connect us via email : query@gtsmeditour.com or whatsapp us +91 9880149003 and get complete health check package from our hospitals in India . early diagnosis and treatment can save life and bring quality of life to the patient.

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