Course Description

What is CMD?

Congenital Muscular Dystrophy (CMD) is a group of inherited muscle disorders present at birth or early infancy, characterized by muscle weakness and hypotonia (low muscle tone).

• “Congenital” means present from birth.

• “Muscular dystrophy” means progressive weakness of muscles due to genetic mutations affecting muscle proteins.

CMD affects voluntary muscles used for movement, posture, and sometimes other organs like the brain or eyes.

???? Causes

CMD is caused by genetic mutations affecting proteins responsible for muscle structure and function.

• Most forms are autosomal recessive (both parents carry a gene).

• Mutations affect proteins like laminin, merosin, collagen, or dystroglycan.

• Can be detected by genetic testing.

???? Symptoms

Symptoms usually appear at birth or in early infancy and may include:

• Weak muscle tone (hypotonia)

• Delayed motor milestones (sitting, crawling, walking)

• Weakness in arms and legs

• Joint contractures or stiffness

• Sometimes, respiratory or heart problems

• Some forms may also have brain or eye involvement

???? Diagnosis

Diagnosis involves a combination of:

1. Clinical examination – observing muscle weakness and developmental delay

2. Creatine kinase (CK) blood test – elevated CK indicates muscle damage

3. Muscle biopsy – examines muscle tissue structure

4. Genetic testing – identifies the specific mutation

5. MRI / imaging – can assess brain or muscle abnormalities in certain CMD types

???? Types of CMD

Some common types include:

1. Merosin-deficient CMD (MDC1A) – most common; affects laminin protein

2. Ullrich CMD – joint contractures and loose joints

3. Alpha-dystroglycan-related CMD – can involve the brain

4. Rigid Spine CMD – affects spine mobility and posture

????️‍♂️ Management / Treatment

There is no cure for CMD yet. Treatment focuses on symptom management and improving quality of life:

• Physiotherapy – maintain muscle strength and flexibility

• Occupational therapy – assist with daily activities

• Respiratory support – ventilators if needed

• Orthopedic interventions – braces, surgeries for contractures

• Cardiac and neurologic care – monitor heart and brain involvement

• Genetic counseling – for families planning future children

???? Prognosis

• Depends on type of CMD and severity

• Some types have slow progression, allowing mobility into adulthood

• Others may cause severe muscle weakness and respiratory issues early in life