FAMILIAL CARDIOMYOPATHY, MENTAL-RETARDATION AND MYOPATHY ASSOCIATED WITH DESMIN-TYPE INTERMEDIATE FILAMENTS

The clinical and morphological findings of a familial case affected by mental retardation, severe biventricular hypertrophic cardiomyopathy and vacuolar myopathy are reported. The phenotype of this patient is s imilar to that described by other authors, in which a lysosomal glycog en storage disease with normal acid maltase levels was suspected. Howe ver, in our case the vacuoles were stained by several antibodies direc ted against various sarcolemmal proteins, such as dystrophin and spect rin, and therefore, were not of lysosomal origin. Some of these vacuol es were clearly derived from the splitting of the fibres and invaginat ion of the extracellular space; autophagic vacuoles were not observed. The accumulation of desmin-type, intermediate filaments was demonstra ted on immunocytochemistry both in the skeletal and cardiac muscles. A brother of the propositus was also affected by mental retardation, se vere cardiomyopathy and died suddenly at the age of 24 yr. A cardiomyo pathy and mental subnormality were also present in other male cousins of the proband, while sudden death occurred in several females relativ es, whose intelligence was normal. None of these latter individuals wa s available for further investigation. This report expands the spectru m of desmin associated myopathy and cardiomyopathy to include a famili al condition with associated mental retardation.