Limb Girdle Muscular Dystrophy: Difference between revisions
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== | == Introduction == | ||
Limb Girdle muscular dystrophy (LGMD) is not a single, but a rare group of inherited genetic disorders which are characterizes by progressive weakening of shoulder and hip muscles. LGMD is defined as a muscular dystrophy presenting with predominantly proximal weakness, sparing facial, extraocular, and distal extremity muscles (at least early in the course of the disease<ref>Darras BT, Jones Jr HR, Ryan MM, Darryl C, editors. Neuromuscular disorders of infancy, childhood, and adolescence: a clinician's approach. Elsevier; 2014 Dec 3.</ref>. LGMD has an autosomal pattern of inheritance which can be either dominant or recessive in nature. The classification is alphanumeric with assignation of number ‘1’ or ‘2’ depending on whether they are inherited dominantly or recessively. A letter is added in order of discovery. To date over 50 genetic loci have been identified. Dominantly inherited LGMD is less common and reported to be only 5–10% of all LGMD.<ref>Murphy AP, Straub V. The classification, natural history and treatment of the limb girdle muscular dystrophies. Journal of neuromuscular diseases. 2015 Jan 1;2(s2):S7-19.</ref> | |||
== Clinically Relevant Anatomy == | |||
LGMD is caused by multiple genes encoding for proteins within the sarcolemma, cytosol or nucleus of the myocyte. The result of the defect is that the muscles cannot properly form certain proteins needed for normal muscle function. Several different proteins can be affected, and the specific protein that is absent or defective identifies the specific type of muscular dystrophy. Among the proteins affected in LGMD are α, β, γ and δ sarcoglycans. The sarcoglycans are a family of transmembrane proteins (α, β, γ, δ or ε) involved in the protein complex responsible for connecting the muscle fibre cytoskeleton to the extracellular matrix, preventing damage to the muscle fibre sarcolemma through shearing forces. | |||
The dystrophin glycoprotein complex (DGC) is a membrane-spanning complex that links the interior cytoskeleton to the extracellular matrix in muscle. The '''sarcoglycan complex''' is a subcomplex within the DGC and is composed of several muscle-specific, transmembrane proteins namely (α, β, γ, δ or ε). The sarcoglycans are asparagine-linked glycosylated proteins with single transmembrane domains.<ref>Chockalingam PS, Cholera R, Oak SA, Zheng Y, Jarrett HW, Thomason DB. Dystrophin-glycoprotein complex and Ras and Rho GTPase signaling are altered in muscle atrophy. American Journal of Physiology-Cell Physiology. 2002 Aug 1;283(2):C500-11.</ref><br> | |||
== Pathology == | |||
add text here relating to the mechanism of injury and/or pathology of the condition<br> | add text here relating to the mechanism of injury and/or pathology of the condition<br> | ||
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add links to outcome measures here (see [[Outcome Measures|Outcome Measures Database]]) | add links to outcome measures here (see [[Outcome Measures|Outcome Measures Database]]) | ||
== Management / Interventions | == Management / Interventions == | ||
add text here relating to management approaches to the condition<br> | add text here relating to management approaches to the condition<br> | ||
== Differential Diagnosis | == Differential Diagnosis == | ||
add text here relating to the differential diagnosis of this condition<br> | add text here relating to the differential diagnosis of this condition<br> | ||
== Resources | == Resources == | ||
add appropriate resources here | add appropriate resources here | ||
Revision as of 05:28, 29 March 2021
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Top Contributors - Shreya Pavaskar, Rucha Gadgil, Kim Jackson, Vidya Acharya, Lucinda hampton, Kehinde Fatola, Khloud Shreif and Kirenga Bamurange Liliane
Introduction[edit | edit source]
Limb Girdle muscular dystrophy (LGMD) is not a single, but a rare group of inherited genetic disorders which are characterizes by progressive weakening of shoulder and hip muscles. LGMD is defined as a muscular dystrophy presenting with predominantly proximal weakness, sparing facial, extraocular, and distal extremity muscles (at least early in the course of the disease[1]. LGMD has an autosomal pattern of inheritance which can be either dominant or recessive in nature. The classification is alphanumeric with assignation of number ‘1’ or ‘2’ depending on whether they are inherited dominantly or recessively. A letter is added in order of discovery. To date over 50 genetic loci have been identified. Dominantly inherited LGMD is less common and reported to be only 5–10% of all LGMD.[2]
Clinically Relevant Anatomy[edit | edit source]
LGMD is caused by multiple genes encoding for proteins within the sarcolemma, cytosol or nucleus of the myocyte. The result of the defect is that the muscles cannot properly form certain proteins needed for normal muscle function. Several different proteins can be affected, and the specific protein that is absent or defective identifies the specific type of muscular dystrophy. Among the proteins affected in LGMD are α, β, γ and δ sarcoglycans. The sarcoglycans are a family of transmembrane proteins (α, β, γ, δ or ε) involved in the protein complex responsible for connecting the muscle fibre cytoskeleton to the extracellular matrix, preventing damage to the muscle fibre sarcolemma through shearing forces.
The dystrophin glycoprotein complex (DGC) is a membrane-spanning complex that links the interior cytoskeleton to the extracellular matrix in muscle. The sarcoglycan complex is a subcomplex within the DGC and is composed of several muscle-specific, transmembrane proteins namely (α, β, γ, δ or ε). The sarcoglycans are asparagine-linked glycosylated proteins with single transmembrane domains.[3]
Pathology[edit | edit source]
add text here relating to the mechanism of injury and/or pathology of the condition
Clinical Presentation[edit | edit source]
add text here relating to the clinical presentation of the condition
Diagnostic Procedures[edit | edit source]
add text here relating to diagnostic tests for the condition
Outcome Measures[edit | edit source]
add links to outcome measures here (see Outcome Measures Database)
Management / Interventions[edit | edit source]
add text here relating to management approaches to the condition
Differential Diagnosis[edit | edit source]
add text here relating to the differential diagnosis of this condition
Resources[edit | edit source]
add appropriate resources here
References[edit | edit source]
- ↑ Darras BT, Jones Jr HR, Ryan MM, Darryl C, editors. Neuromuscular disorders of infancy, childhood, and adolescence: a clinician's approach. Elsevier; 2014 Dec 3.
- ↑ Murphy AP, Straub V. The classification, natural history and treatment of the limb girdle muscular dystrophies. Journal of neuromuscular diseases. 2015 Jan 1;2(s2):S7-19.
- ↑ Chockalingam PS, Cholera R, Oak SA, Zheng Y, Jarrett HW, Thomason DB. Dystrophin-glycoprotein complex and Ras and Rho GTPase signaling are altered in muscle atrophy. American Journal of Physiology-Cell Physiology. 2002 Aug 1;283(2):C500-11.
