Central core disease: Difference between revisions

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{{Infobox medical condition (new)
{{Short description|A congenital myopathy characterized by muscle weakness}}
| name            = Central Core Disease
{{Medical resources}}
| synonyms        =  Central core myopathy
| image          = Cell_sample_of_muscle_tissue_with_central_core_disease_(stained_for_contrast).jpg
| caption        = Histopathologic appearance of typical central core disease: NADH-TR, transverse section from the rectus femoris. Marked predominance of dark staining, high oxidative type 1 fibres with cores affecting the majority of fibres. Cores are typically well demarcated and centrally located (→), but may occasionally be multiple and of eccentric location.
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'''Central core disease''' ('''CCD'''), also known as '''central core myopathy''', is an [[autosomal]] [[Dominance (genetics)|dominant]]ly inherited<ref name=ryr>{{cite journal |pmid=12124989 |date=August 2002 |author1=Robinson, Rl |author2=Brooks, C |author3=Brown, Sl |author4=Ellis, Fr |author5=Halsall, Pj |author6=Quinnell, Rj |author7=Shaw, Ma |author8=Hopkins, Pm |title=RYR1 mutations causing central core disease are associated with more severe malignant hyperthermia in vitro contracture test phenotypes |volume=20 |issue=2 |pages=88–97 |doi=10.1002/humu.10098 |journal=Human Mutation}}</ref> [[congenital myopathy|muscle disorder]] present from birth that negatively affects the [[skeletal muscle]]s. It was first described by Shy and Magee in 1956.<ref name=Quinlivan>{{cite journal |author=Quinlivan RM |title=Central core disease: clinical, pathological, and genetic features |journal=Arch. Dis. Child. |volume=88 |issue=12 |pages=1051–5 |year=2003  |pmid=14670767 |url=http://adc.bmj.com/cgi/content/full/88/12/1051 |doi=10.1136/adc.88.12.1051 |pmc=1719384 |name-list-format=vanc|author2=Muller CR |author3=Davis M |display-authors=3 |last4=Laing |first4=NG |last5=Evans |first5=GA |last6=Dwyer |first6=J |last7=Dove |first7=J |last8=Roberts |first8=AP |last9=Sewry |first9=CA}}</ref><ref>{{cite journal |vauthors=Magee KR, Shy GM |title=A new congenital non-progressive myopathy |journal=Brain |volume=79 |issue=4 |pages=610–21 |year=1956 |pmid=13396066 |doi=10.1093/brain/79.4.610|citeseerx=10.1.1.1026.496 }}</ref> It is characterized by the appearance of the [[myofibril]] under the [[microscope]].<ref>{{DorlandsDict|three/000030637|central core disease}}</ref>


==Signs and symptoms==
'''Central core disease''' (CCD) is a rare [[congenital myopathy]] that primarily affects [[skeletal muscle]]s, leading to muscle weakness and other associated symptoms. It is named for the characteristic appearance of "cores" or areas of disorganized structure within the muscle fibers, which can be observed under a microscope.
The symptoms of CCD are variable, but usually involve [[hypotonia]] (decreased muscle tone) at birth, mild delay in [[child development]] (highly variable between cases), weakness of the [[facial muscles]], and skeletal malformations such as [[scoliosis]] and [[dislocation of hip|hip dislocation]].<ref name=Quinlivan/>


CCD is usually diagnosed in infancy or childhood, but some patients remain asymptomatic until adulthood to middle age.<ref>{{cite journal |last1=Talwalkar |first1=SS |last2=Parker |first2=JR |last3=Heffner |first3=RR |last4=Parker |first4=JC |title=Adult central core disease. Clinical, histologic and genetic aspects: case report and review of the literature. |journal=Clin Neuropathol |date=2006 |volume=25 |issue=4 |pages=180-4 |pmid=16866299}}</ref> While generally not progressive, there appears to be a growing number of people who do experience a slow clinically significant progression of symptomatology. These cases may be due to the large number of mutations of ryanodine receptor malfunction, and with continued research may be found to be clinical variants.{{citation needed|date=June 2012}}
==Presentation==
Individuals with central core disease typically present with [[muscle weakness]] that is most pronounced in the [[proximal muscles]] of the body, such as those in the [[hips]], [[thighs]], and [[shoulders]]. This weakness can lead to difficulties with [[motor skills]] such as walking, running, and climbing stairs. In some cases, affected individuals may also experience [[hypotonia]], or decreased muscle tone, which can contribute to [[delayed motor development]] in infants and young children.
 
==Genetics==
Central core disease is most commonly inherited in an [[autosomal dominant]] pattern, meaning that a single copy of the altered gene in each cell is sufficient to cause the disorder. The condition is often associated with mutations in the [[RYR1 gene]], which encodes the ryanodine receptor 1, a protein that plays a critical role in [[calcium ion]] release from the [[sarcoplasmic reticulum]] in muscle cells. This release is essential for muscle contraction.


==Pathophysiology==
==Pathophysiology==
[[Image:Autosomal dominant - en.svg|thumb|right|Central core disease has an autosomal dominant pattern of [[inheritance]].]]
The "cores" seen in muscle biopsies of individuals with central core disease are areas where the normal structure of the muscle fiber is disrupted. These cores lack mitochondria and other essential components, leading to impaired muscle function. The exact mechanism by which RYR1 mutations lead to core formation is not fully understood, but it is believed to involve abnormal calcium handling within the muscle cells.
 
Central core disease is inherited in an [[autosomal]] [[Dominance (genetics)|dominant]] fashion. Most cases have demonstrable mutations in the [[ryanodine receptor|ryanodine receptor type 1]] (''RYR1'') gene,<ref name=ryr/> which are often ''de novo'' (newly developed). People with CCD are at increased risk for developing [[malignant hyperthermia]] (MH) when receiving [[general anesthesia]].<ref name=Quinlivan/>


==Diagnosis==
==Diagnosis==
The diagnosis is made based on the combination of typical symptoms and the appearance on [[biopsy]] (tissue sample) from muscle. The name derives from the typical appearance of the biopsy on [[light microscopy]], where the muscle cells have cores that are devoid of [[mitochondrion|mitochondria]] and specific [[enzyme]]s.<ref name=Quinlivan/>
Diagnosis of central core disease is typically based on a combination of clinical evaluation, [[muscle biopsy]], and genetic testing. Muscle biopsy reveals the characteristic central cores, while genetic testing can identify mutations in the RYR1 gene. [[Electromyography]] (EMG) and other tests may also be used to assess muscle function.


[[Respiratory failure|Respiratory insufficiency]] develops in a small proportion of cases. [[Creatine kinase]] tend to be normal and [[electromyography]] (EMG) shows short duration, short amplitude motor unit action potentials.<ref name=Quinlivan/>
==Management==
There is currently no cure for central core disease, and treatment is primarily supportive. [[Physical therapy]] and [[occupational therapy]] can help improve muscle strength and function, while [[orthopedic interventions]] may be necessary to address skeletal abnormalities. Individuals with central core disease should be monitored for potential complications, such as [[malignant hyperthermia]], a life-threatening reaction to certain anesthetics.


==Treatment==
==Prognosis==
There is no specific treatment but triggering anesthetics are avoided and relatives are screened for ''RYR1'' mutations as these may make them susceptible to MH.<ref name=Quinlivan/>
The prognosis for individuals with central core disease varies widely. Some individuals experience only mild muscle weakness and lead relatively normal lives, while others may have more significant impairments. The risk of malignant hyperthermia is a serious concern and requires careful management during surgical procedures.


==References==
==Related pages==
{{reflist}}
* [[Congenital myopathy]]
== External links ==
* [[RYR1 gene]]
{{Medical resources
* [[Malignant hyperthermia]]
| DiseasesDB      = <!--site down will update in due course-->
* [[Muscle biopsy]]
| ICD10          = {{ICD10|G|71|2|g|70}}
| ICD9            = {{ICD9|359.0}}
| OMIM            = 117000
| eMedicineSubj  = neuro
| eMedicineTopic  = 76
| GeneReviewsNBK  = NBK1391
| MeshID          = D020512
| Orphanet        = 597
}}
{{Diseases of myoneural junction and muscle}}
{{Channelopathy}}


{{DEFAULTSORT:Central Core Disease}}
[[Category:Congenital disorders]]
[[Category:Myoneural junction and neuromuscular diseases]]
[[Category:Muscular disorders]]
[[Category:Autosomal dominant disorders]]
[[Category:Genetic disorders]]
{{dictionary-stub1}}

Revision as of 19:19, 22 March 2025

A congenital myopathy characterized by muscle weakness



Central core disease (CCD) is a rare congenital myopathy that primarily affects skeletal muscles, leading to muscle weakness and other associated symptoms. It is named for the characteristic appearance of "cores" or areas of disorganized structure within the muscle fibers, which can be observed under a microscope.

Presentation

Individuals with central core disease typically present with muscle weakness that is most pronounced in the proximal muscles of the body, such as those in the hips, thighs, and shoulders. This weakness can lead to difficulties with motor skills such as walking, running, and climbing stairs. In some cases, affected individuals may also experience hypotonia, or decreased muscle tone, which can contribute to delayed motor development in infants and young children.

Genetics

Central core disease is most commonly inherited in an autosomal dominant pattern, meaning that a single copy of the altered gene in each cell is sufficient to cause the disorder. The condition is often associated with mutations in the RYR1 gene, which encodes the ryanodine receptor 1, a protein that plays a critical role in calcium ion release from the sarcoplasmic reticulum in muscle cells. This release is essential for muscle contraction.

Pathophysiology

The "cores" seen in muscle biopsies of individuals with central core disease are areas where the normal structure of the muscle fiber is disrupted. These cores lack mitochondria and other essential components, leading to impaired muscle function. The exact mechanism by which RYR1 mutations lead to core formation is not fully understood, but it is believed to involve abnormal calcium handling within the muscle cells.

Diagnosis

Diagnosis of central core disease is typically based on a combination of clinical evaluation, muscle biopsy, and genetic testing. Muscle biopsy reveals the characteristic central cores, while genetic testing can identify mutations in the RYR1 gene. Electromyography (EMG) and other tests may also be used to assess muscle function.

Management

There is currently no cure for central core disease, and treatment is primarily supportive. Physical therapy and occupational therapy can help improve muscle strength and function, while orthopedic interventions may be necessary to address skeletal abnormalities. Individuals with central core disease should be monitored for potential complications, such as malignant hyperthermia, a life-threatening reaction to certain anesthetics.

Prognosis

The prognosis for individuals with central core disease varies widely. Some individuals experience only mild muscle weakness and lead relatively normal lives, while others may have more significant impairments. The risk of malignant hyperthermia is a serious concern and requires careful management during surgical procedures.

Related pages