case study 84 leonidas arvanitis, md. question 1: a 60 year old male presents with generalized...
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![Page 1: Case Study 84 Leonidas Arvanitis, MD. Question 1: A 60 year old male presents with generalized muscle weakness Describe the histologic findings on the](https://reader035.vdocuments.mx/reader035/viewer/2022062322/5697bf851a28abf838c87aa5/html5/thumbnails/1.jpg)
Case Study 84Leonidas Arvanitis, MD
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Question 1:
• A 60 year old male presents with generalized muscle weakness
• Describe the histologic findings on the H&E and NADH stains
• Click here to view H&E and NADH stains
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Answer 1:• H&E stained frozen sections
– Abnormal variation in myofiber sizes (25-100 microns)– Excess of internalized nuclei – Degenerating or regenerating fibers or inflammatory
infiltrates are not seen • NADH-TR reacted sections
– One or two central or eccentric cores in the vast majority of fibers.
– On longitudinal section the cores traverse the length of the fiber.
– No target fibers are seen– The cores involve primarily type 1 fibers
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Question 2:
• Based on the most likely diagnosis what would an ATPase stain show?
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Answer 2:
• Type 1 fiber predominance
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Question 3:
• Would electron microscopy be helpful?
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Answer 3:
• Yes. It would reveal the absence of mitochondria and sarcoplasmic reticulum in core regions
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Question 4:
• What is your diagnosis?
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Answer 5:
• Central core myopathy
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Question 6:• Central core myopathy is caused by
mutations in which gene?
a. RYR1 encoding Ryanodine receptor
b. SEPN1 encoding Selenoprotein N1
c. NEB encoding Nebulin
d. MTM1 encoding Myotubalarin
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Answer 6:• Central core myopathy is caused by
mutations in which gene?
• RYR1 encoding Ryanodine receptor
• SEPN1 encoding Selenoprotein N1
• NEB encoding Nebulin
• MTM1 encoding Myotubalarin
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RYR1 gene
• RYR1 gene encodes for the protein ryanodine receptor, which is a ligand-gated release channel for Ca²´ stored in the terminal cisterna
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Question 7:
• What other condition is the same gene responsible for?
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Answer 7:
• Malignant hyperthermia