The myogenic scapulo-peroneal syndrome. Muscular dystrophy in the K. kindred: clinical study and genetics

Additional study was carried out of six generations belonging to the K. kindred, which were previously investigated by Oransky (1927). Eighteen members of this kindred were studied. In the early stages of the disease a sharp dissimilarity was observed in the phenotypes in the K. kindred, resulting from different rates of development and varying intensity in the course of the disease, so that it ranges from evident scapulo-peroneal amyotrophy to cases resembling Landouzy-Déjerine muscular dystrophy. In the later stages of the disease the clinical data on those affected were noted to be very similar. Muscular dystrophy in the K. kindred has been inherited as an autosomal-dominant type for five generations. The penetrance of the gene is almost complete. The expressivity of the gene varies from abortive to severe forms of disease. From the clinical and genetic data available at the present time, is seems that the muscular dystrophy in the K. kindred is one of the varieties (namely, a descending type with a "jump") of the facio-scapulo-limb (or facioscapulohumeral) muscular dystrophy. The scapulo-peroneal syndrome could be a long stage in the development of the disorder in some members of the K. kindred. As well as muscular dystrophy, some muscle anomalies have been independently inherited in the K. kindred. Apparently, muscular dystrophy and muscle defects are caused by the non-allele genes; this ensures the independent distribution of these signs among the members of the K. kindred.