The congenital muscular dystrophies (CMD, MDC) represent a heterogeneous group of autosomal recessive disorders manifesting in infancy by muscle weakness and hypotonia. Approximately 40 % of patients with CMD have a primary deficiency of the laminin
2 - chain of merosin (laminin- 2) due to mutations in LAMA2 gene. Laminin-2 bound to
-dystroglycan forms a link between actin - associated cytoskeletal proteins and the components of extracellular matrix. Disruption of this axis is responsible for several forms of muscular dystrophy. A unique case of congenital muscular dystrophy simulating a juvenile polymyositis in a muscle biopsy is presented. A profound reduction of
-dystroglycan and less pronounced secondary deficiency of
2-laminin were found. All known forms of CMD were excluded, and the disorder was diagnosed as so far undescribed form of CMD. The mutation in a gene encoding the protein, that seems to play a role in a glycosylation of
-dystroglycan, is presumed.

        Key words: congenital muscular dystrophy - juvenile polymyositis - FKRP -
-dystroglycan.