Becker’s muscular dystrophies

Becker s muscular dystrophies deficiency of dystrophin, a membrane-associated protein, resulting in an increased Ca2+ level in muscle, loss of Ca2+ homeostasis, and inappropriate calpain activity. Spencer, 2000... 

Normal tissue contains small amounts of dystrophin (about 0.002% of total muscle protein), but its absence leads to both muscular dystrophy and fibrosis, a condition of muscle hardening. A different mutation of the same gene causes defective dystrophin, leading to Becker s muscular dystrophy. 

The most common type of muscular genetic disorder is muscular dystrophy of which there are several kinds. Duchenne s muscular dystrophy is characterized by increasing muscular weakness and eventual death. Becker s muscular dystrophy is milder than Duchenne s, but both are X-linked recessive genetic disorders. Other types of muscular dystrophy are caused by a mutation that affects the muscle protein dystrophin, which is absent in Duchenne s and altered in Becker s muscular dystrophies. Other genetic disorders (such as some cardiomyopathies) can affect various muscle tissues. 

All cells contain an inner membrane skeleton of spectrin-like proteins. Red blood cell spectrin was the first member of the spectrin family described. The protein dystrophin present in skeletal muscle cells is a member of the spectrin family. Genetic defects in the dystrophin gene are responsible for Duchenne s and Becker s muscular dystrophies. 

Duchenne s muscular dystrophy is 1)) caused by the absence of the pro-oO / tein dystrophin, which is a structural protein located in the sarcolemma. Dystrophin is required to maintain the integrity of the sarcolemma, and when absent leads to a loss of muscle function, caused by breakdown of the sarcolemma. The gene is X-linked, and mutations that lead to Duchenne s muscular dystrophy generally result from large deletions of the gene, such that dystrophin is absent from the membrane. Becker s muscular dystrophy, a milder form of disease, is caused by point mutations in the dystrophin gene. In Becker s muscular dystrophy, dystrophin is present in the sarcolemma, but in a mutated form. 

Susceptibiity fiictors Genetic Cardiac arrest associated with rhabdomyolysis occurred in a patient with previously undiagnosed Becker s muscular dystrophy undergoing anesthesia involving isoflurane [4 ]. 

Liechti-Gallati, S., Koenig, M., Kunkel, L.M., Frey, D., Boltshauser, E., Schneider, V., Braga, S., and Moser, H., 1989, Molecular deletion patterns in Duchenne and Becker type muscular dystrophy, Hum Genet, 81, pp 343-348. 

Thanh, L T, Nguyen thi Man, Hori, S, Sewry, C A, Dubowitz V., and Morris, G E. (1995) Characterization of genetic deletions in Becker Muscular Dystrophy using monoclonal antibodies against a deletion-prone region of dystrophin. Am J Med Genet 58, 177-186. 

Becker, K., Robb, S. A., Hatton, Z., Yau, S. C., Abbs, S., and Roberts, R. G. (2003). Loss of a single amino acid from dystrophin resulting in Duchenne muscular dystrophy with retention of dystrophin protein. Hum. Mutat. 21, 651. 

Love, D. R., Flint, T. J., Genet, S. A., Middleton-Price, H. R., and Davies, K. E. (1991). Becker muscular dystrophy patient with a large intragenic dystrophin deletion Implications for functional minigenes and gene therapy. /. Med. Genet. 28, 860-864. 

Basset, O., Boittin, F.X., Dorchies, O.M., Chatton, J.Y., van Breemen, C., and Ruegg, U.T., 2004, Involvement of inositol 1,4,5-trisphosphate in nicotinic calcium responses in dystrophic myotubes assessed by near-plasma membrane calcium measurement, J Biol Chem, 279, pp 47092 17100. Baumbach, L.L., Chamberlain, J.S., Ward, P.A., Farwell, N.J., and Caskey, C.T., 1989, Molecular and clinical correlations of deletions leading to Duchenne and Becker muscular dystrophies, Neurology, 39, pp 465 174. 

Koenig, M., Beggs, A.H., Moyer, M., Scherpf, S., Heindrich, K., Bettecken, T., Meng, G., Muller, C.R., Lindlof, M., Kaariainen, H., and et al., 1989, The molecular basis for Duchenne versus Becker muscular dystrophy correlation of severity with type of deletion, Am J Hum Genet, 45, pp 498-506. 

Kumagai T, Miura K, Ohki T, Matsumoto A, Miyazaki S, et al. 2001. Central nervous system involvements in Duchenne/ Becker muscular dystrophy. No to Hattatsu 33 480-486. 

Duchene (DMD) and Becker s (BMD) muscular dystrophy. Progressive number and severity of lesions in muscle fibers leading to inflammation and rapid (DMD) or slow (BMD) loss of fibers. DMD due to deletion of most or all of the gene for dystrophin, BMD due to defective dystrophin. See text. 

At 27 national hospitals, 1092 (51%) of the 2147 inpatients with muscular dystrophy (MD) were receiving LTV and 61% of the patients receiving LTV were undergoing NIPPV in 2005 (Table 1) (10). NIPPV was used for 71% in Duchenne muscular dystrophy, 66% in limb-girdle dystrophy, 61% in myotonic dystrophy, 53% in Becker s MD, and 50% in Fukuyama congenital progressive MD (10). Sixty percent of the patients, on either NIPPV or TIPPV, required 24-hour ventilation. 

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