Myopathy with extrapyramidal signs

Alternate names

Proximal myopathy with extrapyramidal signs

Definition

Myopathy with extrapyramidal signs is a disorder characterized by early childhood onset of proximal muscle weakness (muscles closest to the body’s midline) and learning disabilities.

Cause

It is caused by changes (mutations) in the MICU1 gene.

Inheritance

Autosomal recessive inheritance, a 25% chance

This condition is inherited in an autosomal recessive pattern.

Signs and symptoms

• This condition is characterized by early childhood onset of proximal muscle weakness (muscles closest to the body’s midline) and learning disabilities. The muscle weakness does not progress, but most patients develop progressive atypical involuntary muscle contractions that influence gait, movement, and posture (extrapyramidal signs) that may be disabling.
• Signs and symptoms are variable and include brief, repetitive, jerky and uncontrolled movements caused by muscle contractions (chorea), tremor, abnormal posturing, and involuntary repetitive movements of the mouth and face.
• Other symptoms may include uncoordinated movements (ataxia), a very small head (microcephaly), drooping of the eyelids, wasting of the eye nerve (optic atrophy), and axonal peripheral neuropathy.

Clinical presentation

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed.

30%-79% of people have these symptoms

• Abnormal basal ganglia MRI signal intensity
• Central core regions in muscle fibers
• Centrally nucleated skeletal muscle fibers
• Chorea
• Difficulty running
• Difficulty walking(Difficulty in walking)
• Dystonia
• Global developmental delay
• Increased variability in muscle fiber diameter
• Orofacial dyskinesia
• Progressive extrapyramidal movement disorder
• Progressive extrapyramidal muscular rigidity
• Proximal muscle weakness(Weakness in muscles of upper arms and upper legs)
• Resting tremor(Tremor at rest)

5%-29% of people have these symptoms

• Ataxia
• Microcephaly(Abnormally small skull)
• Mildly elevated creatine kinase
• Ophthalmoplegia(Eye muscle paralysis)
• Optic atrophy
• Peripheral axonal neuropathy
• Ptosis(Drooping upper eyelid)

1%-4% of people have these symptoms

• Abnormality of extrapyramidal motor function
• Specific learning disability
• Tremor

NIH genetic and rare disease info

• NIH info on Myopathy with extrapyramidal signs

Myopathy with extrapyramidal signs is a rare disease.

Resources

Frequently asked questions

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