Congenital muscular dystrophies (CMD) are a genetically and clinically heterogeneous group of primarily muscular diseases with an autosomal recessive type of heredity and very early manifestation of complaints usually already from neonatal age. So-called classical CMD are typically characterized by a marked to severe muscular hypotonia and muscular weakness from the neonatal period, by dystrophic changes in the skeletal muscles, early contractures of the large joints and frequently by changes in the white matter of the CNS, but always by a quite normal mental development. Less than half the cases of CMD are caused by a complete defekt of the extracellular protein of the muscular cell membrane - alpha-2 laminine - merosine. These patients due to muscular weakness can never walk independently, they have contractures of the large joints, on MRI typical hyperintense changes in the white matter of the CNS, there are signs of peripheral neuropathy on the EMG and they have a quite normal mental state. In the submitted paper the authors describe the typical phenotype and clinical findings in two non-related girls with CMD and a complete merosine deficiency. The clinical diagnosis was confirmed by Skin biopsy which revealed in both patients complete merosine absence in the bacal membrane. In one of the patients merosine deficiency was proved also in muscle biopsy. This is in our opinion the first paper on this type of neuromuscular disease in the CR which is obviously more frequent than can be diagnosed at present and obviously frequently escapes the correct diagnosis. In tase of accurate early diagnosis of this serious disease it is possible to offer the family ex post also aimed prenatal diagnosis by immunohistochemical detection of merosine in placental biopsy.

        Key words: congenital muscular dystrophy, complete merosine deficiency