Emery-Dreifuss muscular dystrophy

Jump to navigation Jump to search
Emery-Dreifuss muscular dystrophy
ICD-10 G71.0
ICD-9 359.0-359.1
OMIM 181350 604929 310300
DiseasesDB 31705 Template:DiseasesDB2 Template:DiseasesDB2
eMedicine neuro/513 
MeSH D020389

WikiDoc Resources for Emery-Dreifuss muscular dystrophy

Articles

Most recent articles on Emery-Dreifuss muscular dystrophy

Most cited articles on Emery-Dreifuss muscular dystrophy

Review articles on Emery-Dreifuss muscular dystrophy

Articles on Emery-Dreifuss muscular dystrophy in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Emery-Dreifuss muscular dystrophy

Images of Emery-Dreifuss muscular dystrophy

Photos of Emery-Dreifuss muscular dystrophy

Podcasts & MP3s on Emery-Dreifuss muscular dystrophy

Videos on Emery-Dreifuss muscular dystrophy

Evidence Based Medicine

Cochrane Collaboration on Emery-Dreifuss muscular dystrophy

Bandolier on Emery-Dreifuss muscular dystrophy

TRIP on Emery-Dreifuss muscular dystrophy

Clinical Trials

Ongoing Trials on Emery-Dreifuss muscular dystrophy at Clinical Trials.gov

Trial results on Emery-Dreifuss muscular dystrophy

Clinical Trials on Emery-Dreifuss muscular dystrophy at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Emery-Dreifuss muscular dystrophy

NICE Guidance on Emery-Dreifuss muscular dystrophy

NHS PRODIGY Guidance

FDA on Emery-Dreifuss muscular dystrophy

CDC on Emery-Dreifuss muscular dystrophy

Books

Books on Emery-Dreifuss muscular dystrophy

News

Emery-Dreifuss muscular dystrophy in the news

Be alerted to news on Emery-Dreifuss muscular dystrophy

News trends on Emery-Dreifuss muscular dystrophy

Commentary

Blogs on Emery-Dreifuss muscular dystrophy

Definitions

Definitions of Emery-Dreifuss muscular dystrophy

Patient Resources / Community

Patient resources on Emery-Dreifuss muscular dystrophy

Discussion groups on Emery-Dreifuss muscular dystrophy

Patient Handouts on Emery-Dreifuss muscular dystrophy

Directions to Hospitals Treating Emery-Dreifuss muscular dystrophy

Risk calculators and risk factors for Emery-Dreifuss muscular dystrophy

Healthcare Provider Resources

Symptoms of Emery-Dreifuss muscular dystrophy

Causes & Risk Factors for Emery-Dreifuss muscular dystrophy

Diagnostic studies for Emery-Dreifuss muscular dystrophy

Treatment of Emery-Dreifuss muscular dystrophy

Continuing Medical Education (CME)

CME Programs on Emery-Dreifuss muscular dystrophy

International

Emery-Dreifuss muscular dystrophy en Espanol

Emery-Dreifuss muscular dystrophy en Francais

Business

Emery-Dreifuss muscular dystrophy in the Marketplace

Patents on Emery-Dreifuss muscular dystrophy

Experimental / Informatics

List of terms related to Emery-Dreifuss muscular dystrophy

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Synonyms and keywords: Benign scapuloperoneal muscular dystrophy with early contractures; EDMD; Emery-Dreifuss Syndrome; Muscular Dystrophy, Emery-Dreifuss.

Overview

Emery-Dreifuss muscular dystrophy is a condition that chiefly affects muscles used for movement (skeletal muscles) and heart (cardiac) muscle. Among the earliest features of this disorder are joint deformities called contractures, which restrict the movement of certain joints. Contractures become noticeable in early childhood and most often involve the elbows, ankles, and neck. Most affected individuals also experience slowly progressive muscle weakness and wasting, beginning in muscles of the upper arms and lower legs and progressing to muscles in the shoulders and hips. [1] [2] [3] [4] [5]

Almost all people with Emery-Dreifuss muscular dystrophy have heart problems by adulthood. In many cases, these heart problems stem from abnormalities of the electrical signals that control the heartbeat (cardiac conduction defects) and abnormal heart rhythms (arrhythmias). If untreated, these abnormalities can lead to an unusually slow heartbeat (bradycardia), fainting (syncope), and an increased risk of stroke and sudden death.

The types of Emery-Dreifuss muscular dystrophy are distinguished by their pattern of inheritance: X-linked, autosomal dominant, and autosomal recessive. Although the three types have similar signs and symptoms, researchers believe that the features of autosomal dominant Emery-Dreifuss muscular dystrophy are more variable than the other types. A small percentage of people with the autosomal dominant form experience heart problems without any weakness or wasting of skeletal muscles.

Pathophysiology

Genetics

Mutations in the EMD and LMNA genes cause Emery-Dreifuss muscular dystrophy. The EMD and LMNA genes provide instructions for making proteins that are components of the nuclear envelope, which surrounds the nucleus in cells. The nuclear envelope regulates the movement of molecules into and out of the nucleus, and researchers believe it may play a role in regulating the activity of certain genes.

Most cases of Emery-Dreifuss muscular dystrophy are caused by mutations in the EMD gene. This gene provides instructions for making a protein called emerin, which appears to be essential for the normal function of skeletal and cardiac muscle. Most EMD mutations prevent the production of any functional emerin. It remains unclear how a lack of this protein results in the signs and symptoms of Emery-Dreifuss muscular dystrophy.

Less commonly, Emery-Dreifuss muscular dystrophy results from mutations in the LMNA gene. This gene provides instructions for making two very similar proteins, lamin A and lamin C. Most of the LMNA mutations that cause this condition result in the production of an altered version of these proteins.

Emery-Dreifuss muscular dystrophy can have several different patterns of inheritance. When this condition is caused by mutations in the EMD gene, it is inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. Males are affected by X-linked recessive disorders much more frequently than females. A striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

In females (who have two X chromosomes), a mutation typically must be present in both copies of the EMD gene to cause X-linked Emery-Dreifuss muscular dystrophy. Females who carry one altered copy of the EMD gene usually do not experience the muscle weakness and wasting that are characteristic of this condition. In some cases, however, they may experience heart problems associated with this disorder.

Other cases of Emery-Dreifuss muscular dystrophy result from mutations in the LMNA gene and are considered to have an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder. About 75 percent of autosomal dominant Emery-Dreifuss muscular dystrophy cases are caused by new mutations in the LMNA gene and occur in people with no history of the disorder in their family. In the remaining cases, people with this form of the condition inherit the altered LMNA gene from an affected parent.

Rarely, LMNA mutations can cause a form of Emery-Dreifuss muscular dystrophy that is inherited in an autosomal recessive pattern. Autosomal recessive inheritance means two copies of the gene in each cell are altered. Most often, the parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene but do not show signs and symptoms of the disorder.

Epidemiology and Demographics

X-linked Emery-Dreifuss muscular dystrophy is the most common form of this condition, affecting an estimated 1 in 100,000 people. The autosomal recessive type of this disorder appears to be very rare; only a few cases have been reported worldwide. The incidence of the autosomal dominant form is unknown.

Evaluation

AHA Scientific Statement: Management of Cardiac Involvement Associated With Neuromuscular Diseases

Cardiac Evaluation in Emery-Dreifuss muscular dystrophy (EDMD)

Class I
"1. Individuals with EDMD, regardless of genotype, should be referred for cardiology assessment at the time of EDMD diagnosis, even if asymptomatic. (Level of Evidence: C) "
Class IIa
"1. At least annual evaluation with echocardio- gram, ECG, and ambulatory ECG is reason- able for patients with autosomal dominant and X-linked recessive EDMD. (Level of Evidence: C) "
"2. Annual ECG and ambulatory ECG are reason- able for autosomal recessive EDMD. (Level of Evidence: C) "

Related Chapters

References

  1. Bonne G, Mercuri E, Muchir A, Urtizberea A, Becane HM, Recan D, Merlini L, Wehnert M, Boor R, Reuner U, Vorgerd M, Wicklein EM, Eymard B, Duboc D, Penisson-Besnier I, Cuisset JM, Ferrer X, Desguerre I, Lacombe D, Bushby K, Pollitt C, Toniolo D, Fardeau M, Schwartz K, Muntoni F. Clinical and molecular genetic spectrum of autosomal dominant Emery-Dreifuss muscular dystrophy due to mutations of the lamin A/C gene. Ann Neurol. 2000 Aug;48(2):170-80. PMID 10939567
  2. Boriani G, Gallina M, Merlini L, Bonne G, Toniolo D, Amati S, Biffi M, Martignani C, Frabetti L, Bonvicini M, Rapezzi C, Branzi A. Clinical relevance of atrial fibrillation/flutter, stroke, pacemaker implant, and heart failure in Emery-Dreifuss muscular dystrophy: a long-term longitudinal study. Stroke. 2003 Apr;34(4):901-8. Epub 2003 Mar 20. PMID 12649505
  3. Emery AE. Emery-Dreifuss muscular dystrophy - a 40 year retrospective. Neuromuscul Disord. 2000 Jun;10(4-5):228-32. PMID 10838246
  4. Helbling-Leclerc A, Bonne G, Schwartz K. Emery-Dreifuss muscular dystrophy. Eur J Hum Genet. 2002 Mar;10(3):157-61. PMID 11973618
  5. Raffaele Di Barletta M, Ricci E, Galluzzi G, Tonali P, Mora M, Morandi L, Romorini A, Voit T, Orstavik KH, Merlini L, Trevisan C, Biancalana V, Housmanowa-Petrusewicz I, Bione S, Ricotti R, Schwartz K, Bonne G, Toniolo D. Different mutations in the LMNA gene cause autosomal dominant and autosomal recessive Emery-Dreifuss muscular dystrophy. Am J Hum Genet. 2000 Apr;66(4):1407-12. Epub 2000 Mar 16. PMID 10739764

Sources

Template:Muscular Dystrophy


Template:WikiDoc Sources