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Genetic risk estimates for duchenne dystrophy (DMD) in the absence of DNA eletions in the central region of the dystrophin gene

Mayana Zatz; Maria Rita Passos-Bueno; Debora Rapaport

Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11461, 05499 São Paulo, SP, Brasil

ABSTRACT

In a screening of 164 unrelated Duchenne patients (DMD) done with cDNA probes cf23a and cf56a (which detects about 70% of DNA deletions), it was observed that the frequency of DNA deletions was significantly greater for sporadic (0.56) than inherited cases (0.34). Such a finding has important implications since it is shown that the absence of DNA deletions leads to a greater genetic risk for further pregnancies than if a molecular deletion is found in the proband. It is suggested also that in the absence of a molecular deletion in the propositus a muscle biopsy should be performed for dystrophin study to exclude the diagnosis of an autosomal recessive "Duchenne-like" muscular dystrophy.

Keywords: Duchenne dystrophy; Dystrophin gene.

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