- Email: [email protected]
EM.P.2.13 Overexpression of LARGE strongly increases laminin binding of α-dystroglycan but does not exhibit toxic effects in mice
Abstracts / Neuromuscular Disorders 19 (2009) 543–660
a disturbance in several DG-ECM ligand interactions contributes to the phenotype of the FKRP related variant of Muscle Eye Brain disease and underscores the role of properly glycosylated ADG in the formation and maintenance of basement membranes. doi:10.1016/j.nmd.2009.06.039
EM.P.2.11 Fukutin-related protein expression in murine dystrophic models carrying single and double mutations for dystrophin and LARGE P.C.M. Martins1, D. Ayub-Guerrieri 1, V.L. Ferreira 1, P.C. Onofre-Oliveira 1, G. Monteiro 1, D. Zilbersztajn 1, L.U. Yamamoto 1, C.M.C. Mori 2, L.E.S. Netto 1, M. Vainzof 1 1
Human Genome Research Center (HGRC) IB USP, Institute of Biosciences, University of São Paulo, São Paulo, Brazil, 2 Department of Pathology, FMVZ-USP, São Paulo, Brazil Some severe forms of muscular dystrophy (MD) are associated with defects in the glycosylation of the protein alpha-DG, an important component of the dystrophin–glycoprotein complex (DGC) in muscle sarcolemma, which is responsible for the link between the extracellular matrix and cell cytoskeleton of the muscle. Among them, the two allelic forms MDC1C and LGMD2I are caused by mutations in the gene for the putative glycosyltransferase protein FKRP, and a third form, CMD1D, is caused by mutation of the Large gene, also involved in the glycosylation of alpha-DG. To study the role of FKRP in skeletal muscle undergoing various stages degeneration, we created a polyclonal antibody against the C-terminal domain of FKRP (aa.394–480), and used it to verify the presence and quantity of FKRP in the muscle through western blot analysis. We evaluated animals of different ages, from the murine dystrophic models mdx, Largemyd, and our recently generated double mutant mdx/Largemyd. Detection of a peptide of the expected MW of 50 kDA for FKRP was consistently observed in all strains, and tested ages. However, some additional bands of higher MW were also sporadically observed, which require further characterization to determine whether these are associated with glycosylation and/or age related muscle degeneration differences. In any case, the present results suggest that expression of FKRP, as evidenced by the 50 kDA peptide, remains constant, irrespective of which mutation is impacting the glycosylation pathway, or reducting the DGC due to the lack of dystrophin. Funding by FAPESP, CNPq-INCT, FINEP, ABDIM. doi:10.1016/j.nmd.2009.06.040
EM.P.2.12 Walker-Warburg syndrome: LARGE mutation in two sibs. The difficulty of prenatal diagnosis A. d’Amico1, C. Bruno 2, E. Silvestri 3, P. Alfieri 4, G. Vasco 5, A. Tessa 1, F.M. Santorelli 1, E. Bertini 1, E. Mercuri 5 1
Bambino Gesù Children’s Research Hospital, Laboratory Medicine, Unit of Molecular Medicine, Rome, Italy, 2 G. Gaslini Institute, Muscular and Neurodegenerative Disease Unit, Genoa, Italy, 3 Pathological Anatomy Unit, S. Camillo Hospital, Rome, Italy, 4 Department of Paediatric Neurology, Catholic University, Rome, Italy, 5 Catholic University, Department of Pediatric Neurology, Rome, Italy Walker-Walburg Syndrome (WWS) is a dystroglycanopathy characterized by severe hydrocephalus, type II lissencephaly, ocular defects and congenital muscular dystrophy. WWS, initially associated with POMT1 mutations, has been subsequently found in
555
patients with FKRP, Fukutin and POMT2 mutations. Mutations in LARGE have been only recently reported in 2 cases of WWS. We report a familial case of WWS associated to LARGE mutation. In the proband, fetal US revealed hydrocephalus at 22 weeks and in family history there was a previous pregnancy which was aborted spontaneously at 22 weeks showing severe hydrocephalus. At birth the child had severe hypotonia with poor movements. He also had aortic contraction, persistent Botallo’s ductus, optic nerve hypoplasia and retinal detachment. Brain MRI showed marked hydrocephalus with a large suprasellar cyst pushing the brainstem and third ventricle. Cerebellum appeared hypoplasic and cerebral cortex was thin. Serum CK was 4000 IU/l. Muscle biopsy showed dystrophic features with severe aDG defect. We found a novel homozygous mutation in LARGE. Autopsy of the aborted foetus showed smooth cerebral hemispheres without sulci formation, thin brain stem, small cerebellum and disorganization of brainstem cytoarchitecture. This case raises concerns about genetic counselling. At the time of autopsy of the aborted foetus a diagnosis of WWS and aDG deficiency were overlooked because hydrocephalus was dominant, and the genetics of these forms were poorly known. In case of severe foetal hydrocephalus detailed investigations, including fetal MR, and autoptic examination of the possible aborted fetus with particular investigation for the brainstem should be performed, particularly in young foetus earlier than 22 weeks of gestation. WWS should be taken into account in the case of severe foetal hydrocephalus. As more information on the genetic background is now available for WWS, this would be of important to provide appropriate genetic counselling. doi:10.1016/j.nmd.2009.06.041
EM.P.2.13 Overexpression of LARGE strongly increases laminin binding of a-dystroglycan but does not exhibit toxic effects in mice F. Saito, Z. Xin, M. Ikeda, H. Hagiwara, T. Shimizu, K. Matsumura Teikyo University, Neurology, Tokyo, Japan Dystroglycan (DG) is a central component of dystrophin–glycoprotein complex that links extracellular matrix and cytoskeleton. a-Dystroglycanopathy is a disorder characterized by muscular dystrophy often associated with brain anomaly, mental retardation and eye abnormalities. Mutations of known or putative glycosyltransferases, POMGnT1, POMT1, POMT2, fukutin, FKRP and large, were identified and defective glycosylation of a-DG has been implicated in the pathogenesis of this disorder. Recently, it was reported that overexpression of LARGE strongly increase a function of a-DG and bypasses the defective glycosylation of a-DG in cultured cells deficient in fukutin or POMGnT1. In this study, we generated transgenic mice overexpressing LARGE ubiquitously under the control of CAG promoter and characterized the effect of LARGE on a-DG function in vivo. The LARGE transgenic mice were born according to the Mendelian ratio, grow normally, and were fertile. The mice exhibited no obvious abnormal behavior and the motor function seemed normal. On Western blotting using IIH6, an antibody against sugar chain moiety of a-DG, immunoreactivity of the antibody were strongly increased and the molecular mass of a-DG shifted to >200 kD in several tissues of the transgenic mice including skeletal muscle, heart, brain and peripheral nerve. Also on immunofluorescent analysis, the increased immunoreactivity of IIH6 was observed in these tissues. Substantial increment of laminin binding activity of a-DG was demonstrated by blot overlay assay. Microscopic analysis with H-E staining revealed no significant morphological abnormality in these tissues. These results demonstrate that up-regulation of
556
Abstracts / Neuromuscular Disorders 19 (2009) 543–660
a-DG function is achieved safely by LARGE in vivo. Thus, the restoration of the a-DG function by LARGE provides a possible molecular target to develop therapeutic strategies for a-dystroglycanopathy. doi:10.1016/j.nmd.2009.06.042
CONGENITAL MYOPATHIES I: RYR1 AND RELATED DISORDERS; POSTER PRESENTATIONS G.P.1.01 Phenotypic variations of central core disease O. Paciello 1, A. Tammaro 2, L. Passamano 3, M. Scutifero 3, E. Picillo 3, A. Di Martino 2, S. Papparella 4, L. Politano3 1
University of Naples Federico II, Department of Veterinary Pathology, Naples, Italy, 2 Cardarelli Hospital, Biotechnology Center for Malignant Hyperthermia, Naples, Italy, 3 Second University of Naples, Exp. Medicine – Cardiomyology and Medical Genetics, Naples, Italy, 4 University of Naples Federico II, Department of Veterinary Myology, Naples, Italy Central core disease (CCD) is a dominantly inherited congenital myopathy, first described in 1956 by Shy and Magee. The diagnosis is made from muscle biopsy by the presence of well defined areas devoid of mitochondria and oxidative enzyme stains, in association with characteristic features. It is known that CCD is allelic to malignant hyperthermia (MH) and that both disorders are due to mutations in RYR1 gene, encoding the channel that mediates calcium release into the myofilament space during excitation–contraction coupling. CCD can show a wide spectrum of phenotypic expression, ranging from apparently clinically normal to an inability to attain aid-free independent ambulation. We report some examples of patients showing characteristic cores on muscle biopsy and mutations in RYR1 gene, presenting with atypical phenotypes. In particular one patient, sharing the well known R2508H mutation, has a phenotype resembling LGMD2B, while another, sharing the novel mutation A3022D, was first diagnosed as a Myotonic Syndrome. doi:10.1016/j.nmd.2009.06.043
G.P.1.02 Phenotypic spectrum of core-rod myopathy caused by dominant or recessive RYR1 mutations K.G. Claeys1, N. Monnier 2, P. Laforet 3, G. Brochier 1, A. Ferreiro 4, A. Barois 5, B. Eymard 3, J. Lunardi 6, M. Fardeau 1, N.B. Romero 1 1 Institut de Myologie, AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Unité de Morphologie Neuromusculaire (Pav.RISLER), Paris, France, 2 CHU Grenoble, Laboratoire de Biochimie de l’ADN, Grenoble, France, 3 Institut de Myologie, AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Centre de Référence Neuromusculaire Paris-Est, Paris, France, 4 Université Pierre et Marie Curie (UPMC) Paris 06, INSERM U787, UMR_S787, IFR14, Paris, France, 5 Hôpital Universitaire Raymond Poincaré, Service de Pédiatrie, Garches, France, 6 CHU Grenoble, Laboratoire de Biochimie de l’ADN, Grenoble, France
Congenital myopathies are a heterogeneous group of inherited muscle disorders, characterized by the predominance of a particular histopathological feature on muscle biopsy, such as central cores (CCD) or nemaline rods. CCD is mainly caused by dominant or recessive mutations in the RYR1 gene encoding the skeletal muscle ryanodine receptor 1 protein. The histopathological spectrum associated with RYR1 mutations is however much wider, comprising not only cores but additional other features such as rods. We studied the clinical, muscle imaging and histopathological data in 16 patients
belonging to 5 unrelated families with core-rod myopathy and dominant or recessive RYR1 mutations. A large clinical variability in RYR1-associated core-rod myopathy was revealed, ranging from fetal akinesia to a mild phenotype, similar to the CCD phenotypic spectrum. A considerable variability was also found in the histopathological findings, such as the percentage of rod-containing myofibers, and the position, structure, or number of cores per muscle fiber. This clinico-pathological variability was present even within patients belonging to the same family. Imaging results showed selective involvement of sartorius, adductor magnus and vasti, with relative sparing of rectus femoris and gracilis. Within the lower leg, selective involvement of soleus and lateral gastrocnemius was revealed, whereas the peroneal muscle group and the tibialis anterior were mainly preserved. In the upper limbs slight abnormalities were revealed in 60% of the patients, mainly in biceps brachii, deltoideus and wrist extensors. Cardiac exams were normal. Vital capacity (VC) was slightly decreased to normal in all except one patient. In three patients a test for malignant hyperthermia susceptibility was performed and found positive. We conclude that core-rod myopathy caused by RYR1 mutations revealed a large clinical and histopathological variability, and that RYR1 mutations are a frequent cause of core-rod myopathy. doi:10.1016/j.nmd.2009.06.044
G.P.1.03 King-Denborough syndrome associated with mutations in the skeletal muscle ryanodine receptor (RYR1) gene J. Dowling 1, S. Lillis 2, K. Amburgey 1, S. Leber 1, H. Zhou 3, S. Al-Sarraj 4, E. Wraige 5, S. Abbs 2, C. Sewry 3, F. Muntoni 3, H. Jungbluth6 1
5328 BSRB, 109 Zina Pitcher Place, Division of Pediatric Neurology, Ann Arbor, United States, 2 Guy’s Hospital, Diagnostic DNA Laboratory, London, United Kingdom, 3 Institute of Child Health, UCL, Dubowitz Neuromuscular Centre, London, United Kingdom, 4 King’s College London, Department of Neuropathology, London, United Kingdom, 5 Evelina Children’s Hospital, Department of Paediatric Neurology, London, United Kingdom, 6 Evelina Children’s Hospital & King’s College London, Department of Paediatric Neurology, London, United Kingdom King-Denborough syndrome (KDS) is a rare dysmorphic syndrome with an associated myopathy. In addition to mild proximal weakness, the syndrome features susceptibility to malignant hyperthermia, distinctive features (ptosis, low set ears, high arched palate and webbing of the neck) short stature, cryptorchism in males and skeletal abnormalities such as kyphoscoliosis and exaggerated lumbar lordosis. The diagnosis is often based on clinical criteria, as specific investigations including EMG and muscle biopsy may be normal or show only mild changes. The skeletal muscle ryanodine receptor (RYR1) gene has been implicated in a wide range of neuromuscular phenotypes including the malignant hyperthermia susceptibility (MHS) trait, Central Core Disease (CCD) and subgroups of Multi-minicore Disease (MmD). Despite substantial clinical and pathological overlap between KDS and RYR1related phenotypes, RYR1 to date has been implicated in KDS only in one isolated case whilst many cases remain genetically unresolved. In this study we present clinical, pathological and genetic findings from 4 patients with clinical features of KDS including facial dysmorphic features, short stature, cryptorchism and severe kyphoscoliosis. Histopathological findings ranged from normal to the typical appearance of CCD. Sequencing of the entire RYR1 gene revealed heterozygous RYR1 substitutions in 3 unrelated patients, some of them previously reported in association with MHS phenotypes;the fourth patient is currently being investigated. Interestingly, in two
a disturbance in several DG-ECM ligand interactions contributes to the phenotype of the FKRP related variant of Muscle Eye Brain disease and underscores the role of properly glycosylated ADG in the formation and maintenance of basement membranes. doi:10.1016/j.nmd.2009.06.039
EM.P.2.11 Fukutin-related protein expression in murine dystrophic models carrying single and double mutations for dystrophin and LARGE P.C.M. Martins1, D. Ayub-Guerrieri 1, V.L. Ferreira 1, P.C. Onofre-Oliveira 1, G. Monteiro 1, D. Zilbersztajn 1, L.U. Yamamoto 1, C.M.C. Mori 2, L.E.S. Netto 1, M. Vainzof 1 1
Human Genome Research Center (HGRC) IB USP, Institute of Biosciences, University of São Paulo, São Paulo, Brazil, 2 Department of Pathology, FMVZ-USP, São Paulo, Brazil Some severe forms of muscular dystrophy (MD) are associated with defects in the glycosylation of the protein alpha-DG, an important component of the dystrophin–glycoprotein complex (DGC) in muscle sarcolemma, which is responsible for the link between the extracellular matrix and cell cytoskeleton of the muscle. Among them, the two allelic forms MDC1C and LGMD2I are caused by mutations in the gene for the putative glycosyltransferase protein FKRP, and a third form, CMD1D, is caused by mutation of the Large gene, also involved in the glycosylation of alpha-DG. To study the role of FKRP in skeletal muscle undergoing various stages degeneration, we created a polyclonal antibody against the C-terminal domain of FKRP (aa.394–480), and used it to verify the presence and quantity of FKRP in the muscle through western blot analysis. We evaluated animals of different ages, from the murine dystrophic models mdx, Largemyd, and our recently generated double mutant mdx/Largemyd. Detection of a peptide of the expected MW of 50 kDA for FKRP was consistently observed in all strains, and tested ages. However, some additional bands of higher MW were also sporadically observed, which require further characterization to determine whether these are associated with glycosylation and/or age related muscle degeneration differences. In any case, the present results suggest that expression of FKRP, as evidenced by the 50 kDA peptide, remains constant, irrespective of which mutation is impacting the glycosylation pathway, or reducting the DGC due to the lack of dystrophin. Funding by FAPESP, CNPq-INCT, FINEP, ABDIM. doi:10.1016/j.nmd.2009.06.040
EM.P.2.12 Walker-Warburg syndrome: LARGE mutation in two sibs. The difficulty of prenatal diagnosis A. d’Amico1, C. Bruno 2, E. Silvestri 3, P. Alfieri 4, G. Vasco 5, A. Tessa 1, F.M. Santorelli 1, E. Bertini 1, E. Mercuri 5 1
Bambino Gesù Children’s Research Hospital, Laboratory Medicine, Unit of Molecular Medicine, Rome, Italy, 2 G. Gaslini Institute, Muscular and Neurodegenerative Disease Unit, Genoa, Italy, 3 Pathological Anatomy Unit, S. Camillo Hospital, Rome, Italy, 4 Department of Paediatric Neurology, Catholic University, Rome, Italy, 5 Catholic University, Department of Pediatric Neurology, Rome, Italy Walker-Walburg Syndrome (WWS) is a dystroglycanopathy characterized by severe hydrocephalus, type II lissencephaly, ocular defects and congenital muscular dystrophy. WWS, initially associated with POMT1 mutations, has been subsequently found in
555
patients with FKRP, Fukutin and POMT2 mutations. Mutations in LARGE have been only recently reported in 2 cases of WWS. We report a familial case of WWS associated to LARGE mutation. In the proband, fetal US revealed hydrocephalus at 22 weeks and in family history there was a previous pregnancy which was aborted spontaneously at 22 weeks showing severe hydrocephalus. At birth the child had severe hypotonia with poor movements. He also had aortic contraction, persistent Botallo’s ductus, optic nerve hypoplasia and retinal detachment. Brain MRI showed marked hydrocephalus with a large suprasellar cyst pushing the brainstem and third ventricle. Cerebellum appeared hypoplasic and cerebral cortex was thin. Serum CK was 4000 IU/l. Muscle biopsy showed dystrophic features with severe aDG defect. We found a novel homozygous mutation in LARGE. Autopsy of the aborted foetus showed smooth cerebral hemispheres without sulci formation, thin brain stem, small cerebellum and disorganization of brainstem cytoarchitecture. This case raises concerns about genetic counselling. At the time of autopsy of the aborted foetus a diagnosis of WWS and aDG deficiency were overlooked because hydrocephalus was dominant, and the genetics of these forms were poorly known. In case of severe foetal hydrocephalus detailed investigations, including fetal MR, and autoptic examination of the possible aborted fetus with particular investigation for the brainstem should be performed, particularly in young foetus earlier than 22 weeks of gestation. WWS should be taken into account in the case of severe foetal hydrocephalus. As more information on the genetic background is now available for WWS, this would be of important to provide appropriate genetic counselling. doi:10.1016/j.nmd.2009.06.041
EM.P.2.13 Overexpression of LARGE strongly increases laminin binding of a-dystroglycan but does not exhibit toxic effects in mice F. Saito, Z. Xin, M. Ikeda, H. Hagiwara, T. Shimizu, K. Matsumura Teikyo University, Neurology, Tokyo, Japan Dystroglycan (DG) is a central component of dystrophin–glycoprotein complex that links extracellular matrix and cytoskeleton. a-Dystroglycanopathy is a disorder characterized by muscular dystrophy often associated with brain anomaly, mental retardation and eye abnormalities. Mutations of known or putative glycosyltransferases, POMGnT1, POMT1, POMT2, fukutin, FKRP and large, were identified and defective glycosylation of a-DG has been implicated in the pathogenesis of this disorder. Recently, it was reported that overexpression of LARGE strongly increase a function of a-DG and bypasses the defective glycosylation of a-DG in cultured cells deficient in fukutin or POMGnT1. In this study, we generated transgenic mice overexpressing LARGE ubiquitously under the control of CAG promoter and characterized the effect of LARGE on a-DG function in vivo. The LARGE transgenic mice were born according to the Mendelian ratio, grow normally, and were fertile. The mice exhibited no obvious abnormal behavior and the motor function seemed normal. On Western blotting using IIH6, an antibody against sugar chain moiety of a-DG, immunoreactivity of the antibody were strongly increased and the molecular mass of a-DG shifted to >200 kD in several tissues of the transgenic mice including skeletal muscle, heart, brain and peripheral nerve. Also on immunofluorescent analysis, the increased immunoreactivity of IIH6 was observed in these tissues. Substantial increment of laminin binding activity of a-DG was demonstrated by blot overlay assay. Microscopic analysis with H-E staining revealed no significant morphological abnormality in these tissues. These results demonstrate that up-regulation of
556
Abstracts / Neuromuscular Disorders 19 (2009) 543–660
a-DG function is achieved safely by LARGE in vivo. Thus, the restoration of the a-DG function by LARGE provides a possible molecular target to develop therapeutic strategies for a-dystroglycanopathy. doi:10.1016/j.nmd.2009.06.042
CONGENITAL MYOPATHIES I: RYR1 AND RELATED DISORDERS; POSTER PRESENTATIONS G.P.1.01 Phenotypic variations of central core disease O. Paciello 1, A. Tammaro 2, L. Passamano 3, M. Scutifero 3, E. Picillo 3, A. Di Martino 2, S. Papparella 4, L. Politano3 1
University of Naples Federico II, Department of Veterinary Pathology, Naples, Italy, 2 Cardarelli Hospital, Biotechnology Center for Malignant Hyperthermia, Naples, Italy, 3 Second University of Naples, Exp. Medicine – Cardiomyology and Medical Genetics, Naples, Italy, 4 University of Naples Federico II, Department of Veterinary Myology, Naples, Italy Central core disease (CCD) is a dominantly inherited congenital myopathy, first described in 1956 by Shy and Magee. The diagnosis is made from muscle biopsy by the presence of well defined areas devoid of mitochondria and oxidative enzyme stains, in association with characteristic features. It is known that CCD is allelic to malignant hyperthermia (MH) and that both disorders are due to mutations in RYR1 gene, encoding the channel that mediates calcium release into the myofilament space during excitation–contraction coupling. CCD can show a wide spectrum of phenotypic expression, ranging from apparently clinically normal to an inability to attain aid-free independent ambulation. We report some examples of patients showing characteristic cores on muscle biopsy and mutations in RYR1 gene, presenting with atypical phenotypes. In particular one patient, sharing the well known R2508H mutation, has a phenotype resembling LGMD2B, while another, sharing the novel mutation A3022D, was first diagnosed as a Myotonic Syndrome. doi:10.1016/j.nmd.2009.06.043
G.P.1.02 Phenotypic spectrum of core-rod myopathy caused by dominant or recessive RYR1 mutations K.G. Claeys1, N. Monnier 2, P. Laforet 3, G. Brochier 1, A. Ferreiro 4, A. Barois 5, B. Eymard 3, J. Lunardi 6, M. Fardeau 1, N.B. Romero 1 1 Institut de Myologie, AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Unité de Morphologie Neuromusculaire (Pav.RISLER), Paris, France, 2 CHU Grenoble, Laboratoire de Biochimie de l’ADN, Grenoble, France, 3 Institut de Myologie, AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Centre de Référence Neuromusculaire Paris-Est, Paris, France, 4 Université Pierre et Marie Curie (UPMC) Paris 06, INSERM U787, UMR_S787, IFR14, Paris, France, 5 Hôpital Universitaire Raymond Poincaré, Service de Pédiatrie, Garches, France, 6 CHU Grenoble, Laboratoire de Biochimie de l’ADN, Grenoble, France
Congenital myopathies are a heterogeneous group of inherited muscle disorders, characterized by the predominance of a particular histopathological feature on muscle biopsy, such as central cores (CCD) or nemaline rods. CCD is mainly caused by dominant or recessive mutations in the RYR1 gene encoding the skeletal muscle ryanodine receptor 1 protein. The histopathological spectrum associated with RYR1 mutations is however much wider, comprising not only cores but additional other features such as rods. We studied the clinical, muscle imaging and histopathological data in 16 patients
belonging to 5 unrelated families with core-rod myopathy and dominant or recessive RYR1 mutations. A large clinical variability in RYR1-associated core-rod myopathy was revealed, ranging from fetal akinesia to a mild phenotype, similar to the CCD phenotypic spectrum. A considerable variability was also found in the histopathological findings, such as the percentage of rod-containing myofibers, and the position, structure, or number of cores per muscle fiber. This clinico-pathological variability was present even within patients belonging to the same family. Imaging results showed selective involvement of sartorius, adductor magnus and vasti, with relative sparing of rectus femoris and gracilis. Within the lower leg, selective involvement of soleus and lateral gastrocnemius was revealed, whereas the peroneal muscle group and the tibialis anterior were mainly preserved. In the upper limbs slight abnormalities were revealed in 60% of the patients, mainly in biceps brachii, deltoideus and wrist extensors. Cardiac exams were normal. Vital capacity (VC) was slightly decreased to normal in all except one patient. In three patients a test for malignant hyperthermia susceptibility was performed and found positive. We conclude that core-rod myopathy caused by RYR1 mutations revealed a large clinical and histopathological variability, and that RYR1 mutations are a frequent cause of core-rod myopathy. doi:10.1016/j.nmd.2009.06.044
G.P.1.03 King-Denborough syndrome associated with mutations in the skeletal muscle ryanodine receptor (RYR1) gene J. Dowling 1, S. Lillis 2, K. Amburgey 1, S. Leber 1, H. Zhou 3, S. Al-Sarraj 4, E. Wraige 5, S. Abbs 2, C. Sewry 3, F. Muntoni 3, H. Jungbluth6 1
5328 BSRB, 109 Zina Pitcher Place, Division of Pediatric Neurology, Ann Arbor, United States, 2 Guy’s Hospital, Diagnostic DNA Laboratory, London, United Kingdom, 3 Institute of Child Health, UCL, Dubowitz Neuromuscular Centre, London, United Kingdom, 4 King’s College London, Department of Neuropathology, London, United Kingdom, 5 Evelina Children’s Hospital, Department of Paediatric Neurology, London, United Kingdom, 6 Evelina Children’s Hospital & King’s College London, Department of Paediatric Neurology, London, United Kingdom King-Denborough syndrome (KDS) is a rare dysmorphic syndrome with an associated myopathy. In addition to mild proximal weakness, the syndrome features susceptibility to malignant hyperthermia, distinctive features (ptosis, low set ears, high arched palate and webbing of the neck) short stature, cryptorchism in males and skeletal abnormalities such as kyphoscoliosis and exaggerated lumbar lordosis. The diagnosis is often based on clinical criteria, as specific investigations including EMG and muscle biopsy may be normal or show only mild changes. The skeletal muscle ryanodine receptor (RYR1) gene has been implicated in a wide range of neuromuscular phenotypes including the malignant hyperthermia susceptibility (MHS) trait, Central Core Disease (CCD) and subgroups of Multi-minicore Disease (MmD). Despite substantial clinical and pathological overlap between KDS and RYR1related phenotypes, RYR1 to date has been implicated in KDS only in one isolated case whilst many cases remain genetically unresolved. In this study we present clinical, pathological and genetic findings from 4 patients with clinical features of KDS including facial dysmorphic features, short stature, cryptorchism and severe kyphoscoliosis. Histopathological findings ranged from normal to the typical appearance of CCD. Sequencing of the entire RYR1 gene revealed heterozygous RYR1 substitutions in 3 unrelated patients, some of them previously reported in association with MHS phenotypes;the fourth patient is currently being investigated. Interestingly, in two