Overview of Neuromuscular Conditions in Children
Neuromuscular disorder is a general term that encompasses many different conditions that affect the function of the skeletal muscles. These diseases can have a number of different causes, symptoms and treatments.
Muscular Dystrophy
There are several different types of muscular dystrophy, with varied causes, symptoms and ages of onset.
Congenital Muscular Dystrophy (CMD)
- Cause: Genetic disorder
- Age of onset: Infancy or childhood
- Symptoms: Muscle weakness, seeming "floppy"
- Occurrence: One in 125,000 people
Duchenne Muscular Dystrophy (DMD)
- Cause: Genetic disorder
- Age of onset: Early childhood
- Symptoms: Delayed independent walking in children under 2, older children may have difficulty climbing stairs or getting up from a seated position, enlargement of the calf muscles, learning disabilities
- Occurrence: One in 3,500-5,600 live male births
Becker Muscular Dystrophy (BMD)
- Cause: Inherited
- Age of onset: Infancy or childhood
- Symptoms: Muscle weakness, seeming "floppy"
- Occurrence: One in 18,450 baby boys
Facioscapulohumeral Muscular Dystrophy (FSHD)
- Cause: Missing piece of genetic material
- Age of onset: Late adolescence
- Symptoms: Muscle weakness and wasting in the face, shoulders, upper arms
- Occurrence: About one in 20,000 people
Limb Girdle Muscular Dystrophy (LGMD)
- Cause: Genetic disorder
- Age of onset: Varies from early childhood to adulthood
- Symptoms: Muscle weakness and wasting in the limbs
- Occurrence: 1 in 14,500-123,000 depending on the type
Myotonic Muscular Dystrophy (DM)
- Cause: Genetic disorder
- Age of onset: Varies from early childhood to adulthood
- Symptoms: Difficulty releasing one's grip, weakness of muscles in the hands and feet, difficulty swallowing, abnormal heart rhythm
- Occurrence: 1 in 8,000 people
Dystrophinopathies
Dystrophinopathies are muscle diseases causes by a gene mutation. Mild forms exhibit some muscle cramping, more sever forms can escalate to affect the skeletal and cardiac muscles and result in a diagnosis of BMD or DMD.
Spinal Muscular Atrophy (SMA)
SMA is a neuromuscular disease that affects one in 6,000-10,000 people and is characterized by progressive muscle atrophy, wasting and weakness. There are four types of SMA that affect infants under 1 year old:
- Type I (Werdnig-Hoffman disease): A severe form of the disorder that manifests at birth or shortly thereafter
- Type II: Characterized by muscle weakness that develops in children aged 6 months to 1 year
- An X-linked form in which children typically are born with joint contractures that make movement difficult
- Distal spinal muscular atrophy Type 1: A form that causes progressive muscle weakness in the hands and feet that eventually spreads to the limbs.
Other Neuromuscular Disorders
- Congenital myasthenia gravis syndrome
- Myasthenia gravis
- Lambert-Eaton syndrome
- Brachial plexopathy - also known as Parsonage Turner syndrome
- Charcot Marie Tooth (CMT) and other hereditary neuropathies
- Chronic inflammatory demyelinating polyneuropathy (CIDP)
- Guillain-Barre syndrome
- Friedreich’s ataxia
- Vasculitis
- Amyotrophic lateral sclerosis (ALS) – also known as Lou Gehrig’s disease
- Spinal bulbar muscular atrophy (SBMA) – also known as Kennedy’s disease and X-linked SBMA
For more information on these and other neuromuscular conditions, see our Resources for Patients and Parents page.