Immunohistochemical examination of dystrophin is suggested as a useful method for diagnosing Duchenne carriers for genetic counseling, in the absence of an index case. This study included 17 females with an age range of 6 to 17 (mean 11.97 +/- 3.81) years and without a family history of Duchenne muscular dystrophy but with varying symptoms of muscle disease, high creatine kinase concentrations, myopathic muscle biopsies, and normal karyotype. Clinical severity was scored according to neurological findings. Muscle ultrasonography, cardiac evaluation, and pathologic examination were done. Dystrophinopathy was detected in six cases (35.3%). All of these cases included 8-33% partially dystrophin-deficient fibers and four of them also had 2-23% deficient fibers. Three cases revealed a mosaic pattern of dystrophin staining. Neither age nor clinical findings correlated with dystrophinopathy; creatine kinase concentrations correlated significantly, however.