Dystrophin is lacking in –
Correct Answer: Duchenne's muscular dystrophy
Description: Ans. is 'b' i.e., Dnchenne's muscular atrophy o Duchenne muscular dystrophy is caused due to lack of dvstophinDuchenne muscular dystrophy -o It is an x-linked recessive disorder.o It is caused due to lack of dystrophin (protein) in the muscle.o Lack of dystrophin leads to increased osmotic fragility of muscle fibres, membrane leakage and ultimately muscular dystrophy.Clinical Features -o The age of onset is 2-5years.o Early development of the child is normal, the disease begins to manifest when the child statrts walking,o The child walks clumsily, has difficulty in climbing stairs and the gait is waddling.o Hypertrophy of calf muscle is a characteristic sign and is visible by the age of 4-5 years.o This is called pseudohypertrophy because it is not true hypertrophy of muscles, instead the muscle is replaced by fat and connective tissues.o Pelvic girdle involvement is very common and can be elicited by Gower's sign.o There is characteristic involvement of the muscleo Eventually all muscles are atrophiedo Intelligence is usually subnormalo Patient die in the second decade of life because of respiratory failure or due to associated cardiomyopao Diagnosis of Duchenne's muscular dystrophy is made by -Elevation of the enzymes of the muscle - creatinine phosphokinase.Histopathology demonstrates diffuse changes of degeneration and muscle fibres of varying size.Gene defect in progressive muscular dystrophies.o Duchene muscular dystrophy-Dystrophino Becker's muscular dystrophy-Dystrophino Limb muscular dystrophy-Myotilin Laminin Caveolin Calpain Dysferlino Emery Dreifess-Emerin lamininso Myotonic dystrophy-(DM1) unstable expansion of a CTG trinucleotide repeat. (DM2) DNA expansion of CcTG repeat,o Fascioscapular-Deletion distal 4qo Oculopharyngeal-Expansion poly A RNA binding protein.
Category:
Pathology
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