DISCORDANT LIGHT-MICROSCOPIC, ELECTRON-MICROSCOPIC, AND IN-VITRO CONTRACTURE STUDY FINDINGS IN A FAMILY WITH CENTRAL CORE DISEASE

We report a family that was referred to our laboratory after a fatal m alignant hyperthermia (MH) accident during general anesthesia. Postmor tem study of different muscles of the proband pointed retrospectively to the presence of central core disease (CCD). Of the 8 family members investigated by histology and in vitro contracture testing (IVCT) 5 w ere found to be MI-I-susceptible. Neurological examination was complet ely normal. Histologically, these 5 patients showed a highly variable proportion (6 - 89%) of cores in type 1 fibers on light microscopy. In 3 patients definite central cores were found, in 1 patient multicore disease was diagnosed, and 1 patient presented with a mixed central/pa racentral form. Electron microscopy could detect cores in only 4 out o f 5 patients. These results demonstrate the difficulty to diagnose cen tral or multicore disease and suggest that mixed forms within the same family may occur. The one histologically dubious patient in this fami ly shows that the most sensitive test for the diagnosis of this myopat hy might be the IVCT.