[Disorders of laminins in diseases of myocardial and skeletal muscles].
The Emery-Dreifuss muscular dystrophy is caused by muscular lesions and disorders of cardial rhythm and/or by cardiomyopathy. An autosomal dominant form is related to mutations of genes, which are coding for lamins A/C.


METHODS
In the group A the authors examined 37 patients with the diagnosis of dilatation cardiomyopathy (DKMP) and the mean ejection fraction 28.4; 8.8%. In the group B of 13 patients a cardiac stimulator was implanted for a rhythm disorder. Both groups were subjected to cardiological, neurological, clinical and electromyographic (EMG) examinations. A muscle biopsy from m. vastus lateralis was made and the sample was evaluated by histology, histochemistry and immunohistochemistry. The coding sequences of genes for lamins were amplified by polymerase chain reaction and the products were analyzed by the DHPLC method (denaturing higher performance liquid chromatography).


RESULTS
In the group A there was a clinically myopathic picture in three patients, while EMG examination revealed a myogenic finding in 12 patients and a marginally myogenic one in five patients. The histological finding in 12 patients was evaluated as myogenic and marginally myogenic in six. In one patient the mutation analysis revealed mutation in the gene for lamin A/C. A myogenic finding in this patient was determined by EMG as well as by histological examination and the autosomal dominant form of the Emery-Dreifuss muscular dystrophy was therefore diagnosed. In the group B one patient displayed a myopathic neurological finding and a myogenic finding during EMG. A subsequent mutation analysis revealed a mutation in the gene for lamin A/C. The case was therefore the autosomal dominant form of the Emery-Dreifuss muscular dystrophy. In the other patients the clinically marginal myopathic finding was observed once, a marginally myogenic finding during EMG was seen five times, histology and immunochemistry revealed a myogenic finding once and a marginally myogenic finding also once. The other findings were within normal range.


CONCLUSIONS
A careful neurological examination including EMG determined symptoms of skeletal muscle myopathies in a surprisingly high percentage of our cardiological patients. This observation draws attention to the need of neurological examination in patients with DKMP in order to discovered disorder in this area in time. In two patients mutations in genes coding lamins A/C were detected. It would be useful to analyze also genes coding for other cytoskeletal proteins in the future.
D000328:Adult; D002311:Cardiomyopathy, Dilated / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D034904:Lamin Type A / Q000235:genetics*; D008297:Male; D020389:Muscular Dystrophy, Emery-Dreifuss / Q000235:genetics*
D034904:Lamin Type A; C440308:lamin C