Distal myopathies.

Advanced molecular genetic possibilities have made it possible to clarify and delineate an ever growing number of distinct new disease entities in the group of distal myopathies. These diseases share the clinical features of preferential muscle weakness in the feet and/or hands, and as they are genetic disorders that lead to progressive loss of muscle tissue they can also be called distal muscular dystrophies. More than 20 entities are currently identified and many are still waiting for genetic characterisation. No final diagnosis can be made on other grounds than by the molecular genetic defect. Besides the usual investigations, including electromyography and muscle biopsy, muscle imaging is very important in defining the precise pattern of muscle involvement. Based on the combination of age at onset, mode of inheritance, pathology and muscle imaging, the list of possible underlying genes can be tracked down to minimal number allowing for specific genetic testing.