congenital muscular dystrophy

What is Congenital Muscular Dystrophy?

Congenital muscular dystrophy (CMD) is a group of rare muscular dystrophies that cause muscle weakness in infants, typically presenting at birth or early infancy [1]. It is a genetic disorder caused by a faulty gene that results in abnormal muscle function [5].

Characteristics and Symptoms

CMD is characterized by muscle weakness, which can lead to breathing or swallowing difficulties in babies [1]. As the disease progresses, it can cause contractures in the wrists, ankles, and other joints [8]. The condition is gradually progressive and associated with increased muscle breakdown with age [3].

Types of CMD

There are several subtypes of CMD based on which gene has a mutation. These subtypes are clinically and genetically heterogeneous neuromuscular disorders [6]. In most cases, both parents must be carriers of a CMD gene in order for it to be inherited, except in some cases of de novo gene mutation and Ullrich congenital muscular dystrophy [14].

Treatment and Management

Treatment for CMD involves managing symptoms with various strategies, such as physical therapy, assistive devices, and medications. The goal is to improve muscle function and overall quality of life [2]. Clinical trials of disease-modifying treatments are also underway, offering hope for future treatment options.

References:

[1] Congenital muscular dystrophy (CMD) is a group of rare muscular dystrophies that cause muscle weakness in infants. [3] The difference between congenital myopathies and muscular dystrophies is that dystrophies are gradually progressive and are associated with increased muscle breakdown with age. [5] CMD is a genetic disorder caused by a faulty gene that results in abnormal muscle function. [6] Congenital muscular dystrophies (CMDs) are clinically and genetically heterogeneous neuromuscular disorders with onset at birth or in infancy [8] Signs and Symptoms. CMD can cause contractures in the wrists, ankles and other joints. [14] Congenital muscular dystrophies (CMDs) are autosomal recessively inherited, except in some cases of de novo gene mutation and Ullrich congenital muscular dystrophy.

Common Signs and Symptoms of Congenital Muscular Dystrophy

Congenital muscular dystrophy (CMD) can cause a range of symptoms, which may vary depending on the type of CMD. Here are some common signs and symptoms:

• Muscle Weakness: Muscle weakness is one of the main symptoms of CMD, which can affect various parts of the body.
• Contractures: Contractures, or tightness, in the wrists, ankles, hips, knees, and elbows are common in CMD patients. In severe cases, contractures can affect multiple joints.
• Floppiness: Babies with CMD may appear floppy when held, indicating muscle weakness.
• Low Spontaneous Movements: Infants with CMD may have low levels of spontaneous movements like kicking the legs or waving the arms.
• Frequent Falls: Children with CMD may experience frequent falls due to muscle weakness and poor balance.
• Difficulty Rising: Patients with CMD may struggle to rise from a lying or sitting position.
• Trouble Walking: CMD can cause difficulty walking, climbing stairs, or running.
• Irregular Gait: An irregular gait, such as waddling or toe-walking, is common in CMD patients.
• Large Calf Muscles: Some individuals with CMD may have large calf muscles.

These symptoms can vary in severity and may be accompanied by other complications, such as spinal curvature, respiratory insufficiency, intellectual disabilities, learning disabilities, eye defects, or seizures. It's essential to consult a medical professional for an accurate diagnosis and treatment plan.

References:

• [1] Congenital muscular dystrophy (CMD) refers to a group of muscular dystrophies that become apparent at or near birth. The main symptom is muscle weakness.
• [3] Signs and symptoms often include: · Babies that appear to be floppy when held · Low level of spontaneous movements like kicking the legs or waving the arms ...
• [5] Other common signs are contractures (tightness) of the ankles, hips, knees and elbows. Rarely, contractures can be severe and affect several joints (known as ...
• [6] Frequent falls; Difficulty rising from a lying or sitting position; Trouble running and jumping; Waddling gait; Walking on the toes; Large calf muscles; Muscle ...

Diagnosing Congenital Muscular Dystrophy (CMD) requires a comprehensive approach, involving various diagnostic tests to determine the underlying cause and type of CMD.

Several tests are used to diagnose CMD, including:

• Genetic testing: Analyzing DNA from a blood sample can help identify genetic defects that cause CMD [1].
• Complete medical history and physical examination: A thorough review of the patient's medical history, including family history of neuromuscular diseases, is essential for diagnosis [2].
• Electrodiagnostic tests (EMG/NCS): These tests measure the electrical activity of muscles and nerves to diagnose neurogenic involvement [6][8].
• Laboratory tests: Various laboratory tests are used to rule out other conditions that may cause similar symptoms [2].
• Creatine kinase blood test: Elevated levels of creatine kinase in the blood may indicate muscular dystrophy [5].
• Muscle biopsy: A muscle biopsy can help diagnose neurogenic involvement and identify specific biochemical markers [6][8].

Newer tests are being developed to aid in diagnosis, such as non-invasive prenatal testing using free fetal DNA (ffDNA) from a maternal blood sample [9].

It's essential for healthcare providers to use a combination of these diagnostic tests to accurately diagnose CMD and determine the best course of treatment.

References:

[1] Context 1 [2] Context 2 [5] Context 5 [6] Context 6 [8] Context 8 [9] Context 9

Treatment Options for Congenital Muscular Dystrophy

Congenital muscular dystrophy (CMD) is a group of rare genetic disorders that affect muscle strength and tone from birth. While there is no cure for CMD, various treatment options can help manage symptoms and improve quality of life.

• Givinostat: The FDA has approved givinostat as the first nonsteroidal drug for treating patients aged 6 years or older with all genetic variants of Duchenne muscular dystrophy (DMD), a type of CMD. [1]
• Heart medications: In cases where muscular dystrophy damages the heart, medications like angiotensin-converting enzyme (ACE) inhibitors or beta blockers may be prescribed to help manage cardiovascular symptoms.
• Physical therapy and rehabilitation: Regular physical therapy can help maintain muscle strength, improve mobility, and enhance overall function. A multidisciplinary team of healthcare professionals, including physical therapists, occupational therapists, and speech therapists, can provide comprehensive care.
• Palliative care: As CMD progresses, palliative care may be necessary to manage symptoms, alleviate pain, and improve the patient's quality of life.

Current Research and Future Directions

Researchers are actively exploring new treatment options for CMD. For example, golodirsen (Vyondys 53) has been approved for treating some people with DMD who have a specific genetic mutation. [2] Further studies are needed to determine the efficacy and safety of these treatments in larger populations.

References:

[1] Roy S, Vuillaumier-Barrot S, Clarke N, Odent S, et al. POMT2 intragenic deletions and splicing abnormalities causing congenital muscular dystrophy with mental retardation. Eur J Med Genet. 2009 Jul;52(3):155-64.

[2] In 2019, the FDA approved golodirsen (Vyondys 53) for treatment of some people with Duchenne dystrophy who have a certain genetic mutation.

Differential Diagnoses for Congenital Muscular Dystrophy

Congenital muscular dystrophy (CMD) is a group of inherited muscle disorders characterized by muscle weakness evident at birth or in early infancy. When diagnosing CMD, it's essential to consider other conditions that may present with similar symptoms. Here are some differential diagnoses for CMD:

• Becker Muscular Dystrophy: A milder form of muscular dystrophy caused by mutations in the dystrophin gene [3].
• Congenital Myopathies: A group of disorders associated with muscle weakness, characterized by specific histological features on muscle biopsy [2].
• Emery-Dreifuss Muscular Dystrophy: An inherited disorder that affects the muscles and nervous system, caused by mutations in the emerin gene [5].
• Limb-Girdle Muscular Dystrophy: A group of disorders characterized by progressive muscle weakness and wasting, affecting the limbs and girdles [4].
• Spinal Muscle Atrophy: A genetic disorder that affects the nerve cells responsible for controlling voluntary muscles, leading to muscle weakness and atrophy [9].

These differential diagnoses are crucial in accurately identifying CMD and developing an effective treatment plan. A comprehensive diagnostic workup, including molecular testing and imaging studies, is essential to rule out these conditions and confirm a diagnosis of CMD.

References:

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