G.P.4.02 Founder effect of a new DYSF exon 48-skipping mutation detected in seven Portuguese dysferlinopathy patients Santos, R. 1,* ; Oliveira, J. 1 ; Vieira, E. 1 ; Coelho, T. 2 ; Carneiro Leite, A. 3 ; Evangelista, T. 4 ; Fortuna, A. 5 ; Geraldo, A. 6 ; Luı ´s, N. 6 ; Guimara ˜es, A. 7 1 Instituto de Gene ´ tica Me ´ dica Dr. Jacinto Magalha ˜ es, Unidade de Gene ´tica Molecular, Porto, Portugal; 2 Hospital Geral de Santo Anto ´ nio, Servic ¸o de Neurofisiologia, Porto, Portugal; 3 Hospital Militar Regional N[o]1, Servic ¸ o de Neurologia, Porto, Portugal; 4 Hospital de Santa Maria, Servic ¸o de Neurologia, Lisboa, Portugal; 5 Instituto de Gene ´ tica Me ´ dica Dr. Jacinto Magalha ˜ es, Unidade de Consulta, Porto, Portugal; 6 Hospitais da Univer- sidade de Coimbra, Servic ¸o de Neurologia, Coimbra, Portugal; 7 Hospital Geral de Santo Anto ´ nio, Unidade de Neuropatologia, Porto, Portugal The allelic muscle disorders known as limb-girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy (MM) and distal anterior com- partment myopathy (DACM) result from defects in dysferlin, a sarco- lemma-associated protein believed to be involved in membrane repair through a process of vesicle fusion. Mutation screening has enabled the diagnosis of dysferlinopathy in 33 Portuguese patients, pertaining to 32 apparently unrelated families, where several known and novel mutations have been detected. One of the newly described mutations, c.5429G>A, was found to coin- cide with a donor splice site and a putative SRp40-responsive ESE. It was shown to promote skipping of exon 48, predictably leading to peptide truncation (p.Gly1781ValfsX17). In the course of this study, several resid- ually expressed products of alternative splicing also involving exons 49 and 50 were detected in mRNA from lymphocytes and muscle tissue both of patients and normal controls. The D48/49/50 isoform was only detected in muscle RNA, presumably representing a product of tissue-specific mod- ulation. The c.5429G>A mutation was present in seven apparently unre- lated patients with heterogeneous clinical presentation. These families all resided (or had ancestry) in a northern interior district of the Country. Intra- and extragenic microsatellite markers as well as several intragenic SNPs were used to establish the haplotypes from patients and random controls. The mutation was seen to be in linkage disequilibrium with one particularly rare haplotype, providing evidence for a common origin. doi:10.1016/j.nmd.2007.06.094 G.P.4.03 Dysferlinopathy in Thai patients and its unusual pathological findings Pongpakdee, S. 1,* ; Sopassathit, V. 1 ; Phudhichareonrat, S. 2 ; Suthiponpaisan, U. 3 ; Goto, K. 4 ; Hayashi, Y. 4 ; Nishino, I. 4 ; Witoonpanich, R. 5 1 Bhumibol Adulyadej Hospital, Neurology unit, Department of Medicine, Bangkok, Thailand; 2 Prasat Neurological Institute, Department of Neuropathology, Bangkok, Thailand; 3 Somdej Prapinklao Hospital, Neurology Unit, Department of Medicine, Bangkok, Thailand; 4 National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Department of Neuromuscular Research, Tokyo, Japan; 5 Rama- thibodi Hospital, Mahidol University, Division of Neurology, Department of Medicine, Bangkok, Thailand Background: Although dysferlinopathy is being increasingly recog- nized in limb-girdle muscular dystrophy and distal myopathy, it has never been reported in Thailand. Objective: To report the first three Miyoshi myopathy patients in Thailand together with interesting pathological find- ings. Method: We studied the clinical features of two siblings and one spo- radic case from two unrelated non-consanguineous families who presented with distal legs weakness. Muscle biopsy was performed in the probands in both families for routine histochemistry, immunohistochemistry and Wes- tern blot analysis for dysferlin. Results: All patients showed wasting and weakness of muscles of the calves. The muscle pathology in one patient showed dystrophic change and inflammatory cell infiltration which are often found in dysferlinopathy, whereas the other showed numerous ring fibers in addition to variation in fiber size. Immunohistochemical and Western blot analyses demonstrated the absence of dysferlin in both mus- cles. Dysferlinopathy is known to show a wide range of abnormalities in myofibrillar alignment from nearly normal to markedly disorganized myo- fibrils showing lobulated fibers and/or moth-eaten fibers in addition to necrotic and regenerating process. However, prominent ring fibers have never been reported. Conclusion: Dysferlinopathy seems to be infrequent in Europe. The observation that it is more prominent in Japan and the most common cause of limb-girdle muscular dystrophy advocates that it may actually be common in other Asian countries as well. Our report probably supports this notion and suggests the presence of more patients with dysferlinopathy in Thailand. Pathologically, one of our cases was characterized by numerous ring fibers. Muscle pathology with frequent ring fibers is seldom seen except in myotonic dystrophy although ring fibers themselves are not disease-specific. This report further widens the variety of dysferlinopathy muscle pathology with prominent ring fibers. doi:10.1016/j.nmd.2007.06.095 G.P.4.04 Dysferlinopathy LGMD2B in children: Description of 3 cases Erazo, R. 1,* ; Henrı ´quez, A. 2 ; Schultz, M. 3 ; Labarca, C. 4 ; Aracena, M. 5 ; Carrasco, J. 2 ; Bascun ˜a ´n, G. 3 ; Soto, V. 6 1 Hospital Luis Calvo Mackenna, Pediatric Neurology, Santiago, Chile; 2 Hospital Luis Calvo Mackenna, Pathology, Santiago, Chile; 3 Clı ´nica Alemana, Pathology, Santiago, Chile; 4 Clı ´nica Alemana, Inter- nal Medicine, Santiago, Chile; 5 Hospital Luis Calvo Mackenna, Genetics, Santiago, Chile; 6 Hospital Luis Calvo Mackenna, Traumatology-Scoliosis, Santiago, Chile Limb-girdle muscular distrophies are a heterogeneous group which may be originated by multiple sarcolemal protein deficits, including dysferlin. Dysferlinopathies are generally manifested by two clinical forms: limb-gir- dle weakness (LGMD 2B) and distal posterior lower limb weakness (Miyo- shi myopathy). Objective. Describe the clinical spectrum of dysferlinopathy in paediatric patients. We describe 3 patients, 1 boy and 2 girls, aged 6, 12 and 18 years, respectively, at the moment of study, during 2004–2006, in Calvo Mackenna Hospital and Clinica Alemana, Santiago, Chile. The 3 patients were born from non-consanguineous parents, and do not have a family history of neuromuscular disorders. The boy (patient 1) had hypoto- nia and motor delay in infancy, he walked at 3.5 years of age. Both girls, patient 2 (12 years old) and patient 3 (18 years old) had no motor delay in infancy. Signs of muscular weakness were detected at 4 years of age in patient 1, because of frequent falls and difficulty climbing stairs and Gow- er’s sign. At 6 years of age he developed scoliosis. Patient 2 and 3 had prox- imal muscular weakness from ages 10 and 12, respectively, manifested by impossibility of climbing stairs, Gower’s sign and frequent falls. Patient 2 developed severe scoliosis and obesity. Patient 3 had myalgias and elevated creatinkinase (CK) of 7000 U/L. Patients 1 and 2 had normal CK values. EMG showed myogenic signs in the 3 patients. Needle muscular biopsy was preformed in patients 1 and 2, and open biopsy in patient 3. All patients had discrete muscular fiber atrophy. Immunohistochemistry study showed normal dystrophin, merosin, alfa sarcoglican, and total deficit of dysferlin in all patients. The clinical presentation of these 3 patients emphasize the importance of discarding dysferlinopathy in all patients with limb-girdle weakness, and also in infants with neuromuscular hypotonia. doi:10.1016/j.nmd.2007.06.096 G.P.4.05 Childhood early onset of LGMD2B in siblings homozygous for the A927fsX21 mutation in the dysferlin gene 788 Abstracts / Neuromuscular Disorders 17 (2007) 764–900