Nemaline myopathy

Nemaline myopathy
Other namesNemaline rod myopathy
SpecialtyNeurology Edit this on Wikidata

Nemaline myopathy (also called rod myopathy or nemaline rod myopathy) is a congenital, often hereditary neuromuscular disorder with many symptoms that can occur such as muscle weakness, hypoventilation, swallowing dysfunction, and impaired speech ability. The severity of these symptoms varies and can change throughout one's life to some extent. The prevalence is estimated at 1 in 50,000 live births.[1] It is the most common non-dystrophic myopathy.[2][3]

"Myopathy" means muscle disease. Muscle fibers from a person with nemaline myopathy contains thread-like[4] rods, sometimes called nemaline bodies.[5] While the rods are diagnostic of the disorder, they are more likely a byproduct of the disease process rather than causing any dysfunction on their own. People with nemaline myopathy (NM) usually experience delayed motor development, or no motor development in severe cases, and weakness may occur in all of the skeletal muscles, such as muscles in the arms, legs, torso, neck flexors, throat, and face. The weakness tends to be more severe in the proximal muscles rather than the distal muscles. The ocular muscles are normally spared.

The disorder is often clinically categorized into groups with wide ranges of overlapping severity, from the most severe neonatal form which is incompatible with life, to a form so mild that it may not be diagnosed since the person appears to function at the lowest end of normal strength and breathing adequacy. Sporadic late onset nemaline myopathy (SLONM) is not a congenital disorder and is considered a different muscle disease from NM, which has its onset at birth or early childhood.[6] Respiratory problems are usually a primary concern for people with all forms of NM, and respiratory infections are quite common. NM shortens life expectancy, particularly in the more severe forms, but aggressive and proactive care allows most individuals to survive and even lead active lives.

Nemaline myopathy is one of the neuromuscular diseases covered by the Muscular Dystrophy Association in the United States.

  1. ^ Yuen, Michaela; Sandaradura, Sarah A.; Dowling, James J.; Kostyukova, Alla S.; Moroz, Natalia; Quinlan, Kate G.; Lehtokari, Vilma-Lotta; Ravenscroft, Gianina; Todd, Emily J. (2014-11-03). "Leiomodin-3 dysfunction results in thin filament disorganization and nemaline myopathy". The Journal of Clinical Investigation. 124 (11): 4693–4708. doi:10.1172/JCI75199. ISSN 0021-9738. PMC 4347224. PMID 25250574.
  2. ^ de Winter, Josine Marieke; Buck, Danielle; Hidalgo, Carlos; Jasper, Jeffrey R.; Malik, Fady I.; Clarke, Nigel F.; Stienen, Ger J. M.; Lawlor, Michael W.; Beggs, Alan H. (2013-06-01). "Troponin activator augments muscle force in nemaline myopathy patients with nebulin mutations". Journal of Medical Genetics. 50 (6): 383–392. doi:10.1136/jmedgenet-2012-101470. ISSN 1468-6244. PMC 3865762. PMID 23572184.
  3. ^ Ottenheijm, Coen A. C.; Lawlor, Michael W.; Stienen, Ger J. M.; Granzier, Henk; Beggs, Alan H. (2011-05-15). "Changes in cross-bridge cycling underlie muscle weakness in patients with tropomyosin 3-based myopathy". Human Molecular Genetics. 20 (10): 2015–2025. doi:10.1093/hmg/ddr084. ISSN 1460-2083. PMC 3080611. PMID 21357678.
  4. ^ nemaline myopathy
  5. ^ "Nemaline Myopathy - NORD (National Organization for Rare Disorders)". NORD (National Organization for Rare Disorders). Retrieved 2016-04-25.
  6. ^ Chahin, Nizar; Selcen, Duygu; Engel, Andrew G. (2005-10-25). "Sporadic late onset nemaline myopathy". Neurology. 65 (8): 1158–1164. doi:10.1212/01.wnl.0000180362.90078.dc. ISSN 1526-632X. PMID 16148261. S2CID 23334154.