Mild clinical and histopathological features in patients who carry the frequent and causative malignant hyperthermia RyR1 mutation p.Thr2206Met.

OBJECTIVE: Malignant hyperthermia (MH) is a classically unapparent pharmacogenetic disorder of the skeletal muscles triggered by inhalational anesthetics or depolarizing muscle relaxants. The disposition to MH is inherited in an autosomal-dominant manner and is primarily due to mutations in the gene for the ryanodine receptor type 1 (RyR1). The present study intended to analyze whether mild muscular symptoms (elevation of the resting CK, cramps in the calves, slight calf hypertrophy) may be associated with susceptibility to MH and/or with histopathological changes. METHODS: A muscle biopsy was taken from 12 out of 44 blood relatives (three generations) of a large family and was investigated with the halothane/caffeine in vitro contracture test (IVCT). Afterwards a histological, histochemical and immunhistological examination was performed. Altogether in 29 persons the DNA was analyzed for mutations in the RyR1-gene. RESULTS: Eight persons were diagnosed as susceptible to MH (MHS) by the IVCT, 4 were MH negative. All MHS persons carried the MH causative c.6617C > T (Thr2206Met) mutation and showed slight clinical signs of a myopathy as well as mild biopsy changes with isolated hypotrophic fibers and disseminated small areas with reduction of oxidative staining (multi-minicore like lesions). The Thr2206Met mutation was identified in another further 9 relatives who also experienced mild myopathological features. Clinical MH incidents were not reported in this large family. CONCLUSION: The RyR1 Thr2206Met mutation is one of the most frequent mutations in the European MH population but carriers are normally healthy. In this study we could demonstrate that the MH causative Thr2206Met mutation may also be associated both with clinical symptoms of a mild myopathy and histopathological changes in the oxidative inter myofibrillar network.

[Facioscapulohumeral muscle dystrophy and heart disease]. / Fazioskapulohumerale Muskeldystrophie mit Herzbeteiligung.

Cardiac involvement is well known in a number of skeletomuscular diseases but not in facio-scapulohumeral muscular dystrophy (FSHD). We report on a 71 year old woman with progressive cardiac insufficiency in FSHD, which was also confirmed by molecular analysis in one of the two daughters affected by the disease. Autopsy of the deceased patient showed the typical changes in skeletal muscles including focal inflammatory infiltrates in the diaphragm and, in addition, cardiac muscular involvement. The histological changes resembled those seen in primary cardiomyopathy despite the normal muscle mass volume. Both clinically and morphologically, the cardiac disease was the cause of death in this patient with FSHD.

[Neuropathological findings after cardiac surgery-retrospective study over 6 years]. / Neuropathologische Befunde nach herzchirurgischen Operationen. Retrospektive über 6 Jahre.

Neuropathological studies may contribute to the discovery of central nervous system complications after heart surgery and thus help to reduce the incidence of postoperative neurological or cognitive disturbances. We examined the brains of 262 such patients operated for coronary bypass, valve replacement, or heart transplantation. Circulatory disturbances (macro- and microhemorrhages, infarcts, subarachnoid hemorrhages, and hypoxemic brain damage) were present in 128 cases (49%), as the cause of death in 33 cases (12.6%). The infarcts were caused by local arteriosclerosis of brain arteries, arterial emboli originating from the operative sites or myocardial infarctions, or by fat emboli, foreign body emboli or megakaryocytic capillary emboli in rare cases. Inflammatory disturbances were present in 17 cases and consisted of fungal or bacterial septicopyemic changes (12) or of glial nodules (5) as the substrate of a viral or autoimmunencephalitis (Bickerstaff). An incidental finding was Alzheimer's disease in 37 cases (14% of the material) of elderly patients, often associated with cerebral amyloid angiopathy but not as cause of death or cause of macroscopic brain hemorrhage. Since we have conducted an autopsy study, there is a limitation to transfer the documented changes to the total group of post-cardiac surgery patients with neurologic and cognitive deficits. Contrary to some previous reports, histologically overt microembolic phenomena do not seem to play a major role in our material. On the other hand, careful scrutiny revealed non-fatal white matter microhemorrhages of varying frequency in the different groups, especially after valve operations. These as well as the occasional glial nodules, after resorption and microscarring, could well be the cause of slight neurologic and cognitive impairments.