Nemaline Myopathy

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Nemaline Myopathy is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Nemaline myopathy is a rare genetic muscle disorder. Six different clinical subtypes of nemaline myopathy have been identified based on disease severity and age of onset, ranging from a severe congenital-onset (at birth) form that is usually lethal in the first few months of life, through to less severe forms with onset in childhood or adulthood. Most affected individuals have a milder form of the disorder known as typical congenital nemaline myopathy and are able to walk and lead active lives. The inheritance pattern is variable depending on the underlying genetic cause. Characteristic symptoms of all forms of nemaline myopathy include muscle weakness, diminished muscle tone (hypotonia), and reduced or absent reflexes. In most people, muscle weakness is static (nonprogressive) over time. Weakness of the muscles of breathing and swallowing are the major cause of morbidity and mortality.

Nemaline myopathy is defined by muscle weakness and the presence of fine, thread-like or rod-like structures called "nemaline bodies", when muscle biopsies are viewed under the microscope. The prefix "nema-" is derived from Greek and means "thread-like." Nemaline bodies consist of accumulations of muscle proteins due to mutations in genes which encode proteins components of the muscle thin filament.

Supporting Organizations

Foundation Building Strength for Nemaline Myopathy

2450 El Camino Real
Suite 101
Palo Alto, CA 94306
Tel: (650)320-8000

Muscular Dystrophy Association

3300 East Sunrise Drive
Tucson, AZ 85718-3208
Tel: (520)529-2000
Fax: (520)529-5300
Tel: (800)572-1717

Muscular Dystrophy Campaign

61 Southwark Street
London, SE1 0HL
United Kingdom
Tel: 2078034800

Nemaline Myopathy Support Group


For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  9/29/2015
Copyright  2015 National Organization for Rare Disorders, Inc.

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Nemaline Myopathy