64444ournal ofNeurology, Neurosurgery, and Psychiatry 1993;56:644-648 Familial desminopathy: myopathy with J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.56.6.644 on 1 June 1993. Downloaded from accumulation of desmin-type intermediate filaments Jiri Vajsar, Laurence E Becker, Robert M Freedom, E Gordon Murphy Abstract lings who presented with cardiomyopathy and Two siblings developed cardiomyopathy clinically silent myopathy.7 During the follow- several years before slowly progressive ing years, however, they have both developed muscle weakness. Skeletal muscle biopsy slowly progressive muscle weakness. In this specimens showed subsarcolenumal cres- paper, we characterise histochemically, cents of dark eosinophilic material in immunohistochemically, and ultrastructurally both type I and type II fibres. Immuno- the increased number of deposits of subsar- histochemically the subsarcolemmal colemmal material found in repeated muscle material stained positively for the inter- biopsy specimens. mediate filament protein desmin and for the heat shock protein ubiquitin but for no other cytoskeletal proteins. Ultra- Patients and methods structurally the subsarcolemmal deposits PATENTS consisted of aggregates of granular and Patient I filamentous material arising from Z- A five year old girl whose parents are second bands. Follow up muscle biopsies six cousins presented with excessive tiredness, years later showed an increased number effort intolerance, and epigastric pain. of the muscle fibres that contained sub- Examination revealed gallop rhythm, sarcolemmal aggregates that stained enlarged left atrium, and deep T-wave inver- positively for desmin and ubiquitin. sion on ECG in the left precordial leads. These clinical and pathological features Cardiac catheterisation at six years showed characterise a rare familial myopathy elevated left ventricular end diastolic pressure associated with an unusual distribution and pulmonary artery wedge pressure consis- of desmin intermediate filament proteins tent with the reduced compliance of her left in skeletal and probably also cardiac ventricle. There was also evidence of thicken- muscle. ing of the left ventricular wall. Although she was not complaining of muscle weakness, an (7 Neurol Neurosurg Psychiatry 1993;56:644-648) EMG performed at the age of 11 showed myopathic changes in the gastrocnemius muscle. Results of tests for nerve conduction, http://jnnp.bmj.com/ Intermediate filaments represent one of the creatine kinase, lactate dehydrogenase, and three main cytoskeletal protein filament sys- concentrations of total and free carnitine in tems of most vertebrate cells. The filaments, serum were all normal. She then had an open which are 10 to 15 nm wide, can be divided muscle biopsy from the triceps muscle. By the into four distinct sequence types, numbered I age of 17 she had developed muscle weak- to IV.' Acidic keratins are type I filaments; ness. Examination showed generally reduced neutral-basic keratins, type II; desmin, muscle bulk and diminished deep tendon vimentin, and glial fibrillary acidic protein, reflexes. Muscle strength was decreased to on September 23, 2021 by guest. Protected copyright. type III; and neurofilaments, type IV. Desmin four fifths in her arms and legs; proximal and vimentin represent the main components muscle groups were slightly weaker. She had The Hospital for Sick of intermediate filaments in skeletal and an incomplete Gowers' sign and tired easily Children, and the smooth muscle cells. Immunoelectron when running. The results of her mental University ofToronto, microscopy has shown that desmin surrounds examination were normal. Toronto, Ontario, Electrocardio- Canada the myofibrils at Z-disc levels and anchors the graphic examination showed left ventricular Division ofNeurology myofibrils in the transverse register as well as hypertrophy with strain. The results of J Vajsar to the sarcolemma." The network of inter- repeated measurements of creatine kinase in E G Murphy mediate filaments connects the plasma mem- serum and of forearm lactic ischaemic tests Division of brane skeleton with the nuclear lamina or were normal. A second biopsy of the triceps Neuropathology karyoskeleton. muscle was performed. L E Becker Abnormal expression of desmin has been Division of Cardiology R M Freedom seen in tumours derived from smooth and Patient 2 skeletal muscle,4 muscle Correspondence to: regenerating fibres,5 The first patient's brother developed transient Dr Vajsar, Division of and congenital and late onset myopathies congestive heart failure at two years. Neurology, 555 University with or Avenue, Toronto, Ontario, without cardiomyopathy.6 Cardio- Examination revealed palpable gallop and Canada M5G 1X8. myopathy may develop during the course of quadruple rhythm with third and fourth heart Received 25 June 1992 the disease but has not been reported as a sounds. ECG showed decreased contractility and in revised form 14 September 1992 presenting feature. of the left ventricle and diffuse S-T depres- Accepted 28 September 1992 We have previously reported on two sib- sion and T-wave inversion in the left precor- Familial desminopathy: myopathy with accumulation ofdesmin-type intermediatefilaments 645 Figure I Muscle biopsy obtained for electron microscopy. J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.56.6.644 on 1 June 1993. Downloaded from specimen shownng subsarcolemmal deposits of Limited muscle biochemistry showed nor- dark eosinophilic material A~~~~~~A mal activity of the following glycolytic in most musclefibres fi; ;~~~.K~~~~~~~~~~~;e ... enzymes: acid maltase, debranching enzyme, (HE, x 800). phosphorylase, phosphofructokinase, phos- X........ phoglycerate kinase, and phosphoglycerate *; ~~~~~~~~~~~~~~~~~~~~~~~~~~.. mutase. ,~~~~~~~W, PATHOLOGICAL RESULTS Light microscopy, histochemistry, and immunohistochemistry Mild variation in fibre size and a few atrophic fibres were seen on cross and longitudinal sections in both patients. No fibre degenera- tion or regeneration, however, was present in any of the four specimens. There was dial leads. This boy, bor at termn, had devel- increased internalisation of nuclei and mild oped hypoxic-ischaemnic encephalopathy focal endomysial fibrosis. The most striking because of meconium aspiration at birth. finding was the presence of deposits of dark This was followed by a seizure disorder and eosinophilic subsarcolemmal material (fig 1). global developmental delay: he walked at the The subsarcolemmal deposits showed identi- age of 3 1/2 years and spoke only single words cal positive staining in all four specimens at the age of 6. Electromyography yielded (table). On ATPase, the material was seen in normal results and his serum creatine kinase both type I and II fibres. concentration was normal at the age of 5 The histogram showed that 75% (patient when he underwent a biopsy of the triceps 1) and 70% (patient 2) of fibres were type I. muscle. By the age of 11 he had difficulty ris- The average diameter of type I fibres in ing from the floor. Examination indicated he patient 1 increased over six years from 32 to was mentally retarded. Muscle bulk was 45 p and the average diameter of type II reduced and muscle strength was four fifthis fibres from 43 to 56,u. In patient 2 the size of diffusely but slightly better distally. Deep ten- type I fibres increased over six years from 21 don reflexes were brisk and a partial Gowers' to 36 ,u, whereas the size of type II fibres sign was present. Electrocardiographic exami- decreased from 25 to 21 p. nation showed left ventricular hypertrophy When the immunoperoxidase technique with strain. Serum creatine kinase concentra- with antisera to myosin, ubiquitin, vimentin, tion was again normnal and another biopsy of desmin, a actinin, actin, keratin, and glial fib- the triceps muscle was performed. rillary acidic protein was performed, crescents of subsarcolemmal material stained positive MUSCLE BIOPSIES only with antisera to desmin (fig 2a, 2b) and Two open biopsies from the right triceps ubiquitin (fig 3). The muscle fibres contain- muscle for each child were performed 6 years ing material positive for desmin were calculat- apart. Serial sections embedded in paraffi ed in three different microscopic fields (50 http://jnnp.bmj.com/ and frozen were prepared for conventional fibres/field). In patient 1 the deposits were histological, histochemical, and immunohis- initially present in an average of 22% of tochemical examinations (table). Dewaxed muscle fibres, which increased to 68% in the and rehydrated paraffin sections were stained second biopsy from the same muscle six years with commercially available antibodies later. In patient 2 the material was present (Dakopatts, Denmark) to localise desmin and initially in 14% and later in 66% of muscle ubiquitin immunoreactivity. Semi-thin sec- fibres. on September 23, 2021 by guest. Protected copyright. tion fixed with osmium and stained with tolu- idine blue were examined and thin sections ELECTRON MICROSCOPY The findings on electron microscopy were similar for both children. There were focal Table Results of staining subsarcolemmal deposits in all subsarcolemmal areas of muscle fibres that four biopsy specimens in two siblings with cardiomyopathy andprogresssive muscle weakness showed aggregates of granular and filamen- tous material (fig 4, fig 5a, 5b). The aggre- Stain Staining or reactiviy gates varied in size and occasionally could be Gomori's modified trichrome Dark green discerned arising and