Skip to Main Content

++

Rare, congenital, slowly progressive inherited neuromuscular disease that usually is apparent at birth; characterized by extreme hypotonia.

++

Nemaline Myopathy.

++

Nemaline myopathy has been classified into four major subtypes:

++

Severe neonatal form: Characterized by severe muscle hypotonia with little spontaneous movements, severe dysphagia and absence of sucking ability, and respiratory problems that are considered life-threatening during the first weeks or months of life. A fetal form (“fetal akinesia sequence") has been suggested but is still considered part of this entity. It is associated with large quantity of amniotic fluid, abnormal muscle growth, and underdevelopment of the lung.

++

Mild congenital or “classic" form: Age at onset between birth and the first years of life. It is characterized by extreme muscle weakness, feeding difficulties, delayed motor development (e.g., walking difficulties, speech abnormalities), and respiratory complications that are not considered as severe at the neonatal form. The evolution of the disease is often static or very slowly progressive. Most affected individuals can have an active life; others may experience deterioration during the period of rapid growth before puberty.

++

Childhood-onset form: Age at onset between 10 and 20 years. The apparition of muscle weakness is slowly progressive and allows motor development to be considered normal. The clinical symptoms typically progress during childhood, but exercises that increase muscle development and strength may offset the progression of the disease.

++

Late-onset or adult-onset form: Characterized by the absence of family history or symptomatology before the apparition of the muscle weakness, which is mostly apparent in the extremities and the trunk.

++

Affects females more than males; estimated incidence is 2:10,000 live births.

++

Two clinically indistinguishable types are described. Type I is autosomal dominant with incomplete penetrance and is caused by a defect in the gene TPM3 (or NEM1) located on chromosome 1q21-q23 and encoding for tropomyosin-3. Type II is autosomal recessive and is caused by a mutation of the gene NEM2 located on chromosome 2q21.2-q22 and encoding for nebulin.

++

All muscles, including the diaphragm, may be affected. The disease is nonprogressive or slowly progressive. Cardiac involvement is rare, but cases of cardiomyopathy in adults have been described.

++

Serum creatine kinase levels are usually, but not always, normal. Muscle biopsy shows disproportion of type I muscles fibers and subsarcolemmal rod-like structures made of excessive Z-band material.

++

In the neonatal period, hypotonia and muscle weakness produce swallowing problems and weak cry; severe cases progressing rapidly to respiratory failure are described. Motor development (walking) is delayed. Muscle mass is thin; truncal and proximal muscles are most affected, but distal limb, pharyngeal, and facial muscles can be involved. The face is usually long with a high-arched palate, malocclusion, prognathism, or micrognathia. Abnormal gait. Normal intelligence. Scoliosis and intercostal muscle weakness produce severe restrictive lung disease. Congenital heart disease or cardiomyopathy may be rarely present.

++

...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessAnesthesiology Full Site: One-Year Subscription

Connect to the full suite of AccessAnesthesiology content and resources including procedural videos, interactive self-assessment, real-life cases, 20+ textbooks, and more

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessAnesthesiology

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.