This international ENMC workshop assembled 18 clinicians and scientists from Europe, the United States of America, South America, Japan and Australia to discuss “Rare Structural Congenital Myopathies (CM)”. This workshop can be considered a follow-up to an earlier one [1], then and now excluding classical CM on which separate workshops have repeatedly been held at ENMC and respective consortia exist such as on nemaline myopathies, centronuclear myopathies, core myopathies, as well as protein aggregate myopathies. CM can be classified according to CM-specific morphological features, certain epidemiological aspects or on molecular grounds. This workshop addressed those rare CM which, to date, have not been assigned to any known genes by virtue of identifying disease causing mutations. Of the approximately 10 CM discussed at the earlier workshop [1] seven have now been clarified molecularly. The workshop concentrated on the remaining three and other rare CM, i.e., tubular aggregates myopathy, cylindrical spirals myopathy, crystalline body myopathy, as well as fingerprint and Zebra bodies myopathies with the goal to characterise them nosologically and to develop further strategies towards their molecular clarification. Since these CM are very rare, it was crucial to perform archival searches in major large neuromuscular centres across the globe and to obtaining relevant clinical findings from patients and their families in preparation for this workshop. Moreover, the suitability of various