[Molecular genetic investigations in muscular diseases].

The last couple of years have witnessed a rapid development in discoveries of the genetic background in myopathies. It is therefore timely to review the impact they have on clinical work. The recognition of a myopathy remains a clinical activity, and biopsy retains a major role. Molecular genetic investigation can be contemplated early in cases with certain typical clinical presentation. In others, the correct indication to such an investigation can only be made based on findings at biopsy. The information of precise mutation can be used for genetic counselling of the family. Knowledge of genes, whose mutations are sufficient to cause certain myopathies, have provided a great amount of knowledge about pathophysiological mechanisms involved. Some are arguably rare diseases, however, this knowledge also helps understand more frequent myopathies, as it has been the case in neurodegenerative disorders.