Dystrophinopathies in females

Various laboratory tests were performed to establish carriership in 24 familial and sporadic carriers of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). The activity of creatine kinase was in all females but one, very high and significantly higher in isolated carriers; quantitative EMG indicated myopathic changes, muscle biopsies revealed different degrees of changes--from a variability of muscle fibers size and central nuclei to severe dystrophic features. Immunohistochemical evaluation of dystrophin revealed, in all females but one, mosaic pattern of staining--a mixture of dystrophin-positive and dystrophin-negative fibers, the latter consist 15-30% of all fibers. Quantitative evaluation of dystrophin showed a reduced abundance with normal or abnormal molecular weight. The abnormalities were more expressed in sporadic cases. The detection of sporadic carriers, particularly the non-manifesting clinical, is a very important progress--it permits the correct diagnosis (before, these females were diagnosed as limb girdle muscle dystrophy (LGMD) and supply them with the benefit of genetic counselling, which also requires some modification.