dates should be monitored closely, but exudates threatening the macula will mandate urgent treatment. http://dx.doi:10.1016/j.nmd.2012.06.324 EMERY-DREIFUSS MUSCULAR DYSTROPHY AND FHL-1 RELATED CONDITIONS - POSTER PRESENTATIONS G.P.119 How mutations in the FHL1 gene lead to severe muscle disease B.R. Wilding , M.J. McGrath, C.A. Mitchell Monash University, Department of Biochemistry and Molecular Biology, Clayton, Australia The LIM domain containing protein FHL1 promotes skeletal muscle growth however mutations in FHL1 gene cause four different muscle dis- eases: Reducing Body Myopathy (RBM), Scapuloperoneal Myopathy (SPM), X-Linked Myopathy with Postural Muscle Atrophy (XMPMA) and Emery-Dreifuss Muscular Dystrophy (EDMD). Protein aggregation and childhood lethality occur in RBM, while XMPMA and EDMD exhi- bit adult onset with no protein aggregation. How FHL1 mutations lead to muscle disease and why severity differs between these diseases is unknown. We hypothesised that FHL1 mutations disrupt key structural residues, leading to miss-folding and the formation of reducing bodies which are unique to RBM. Aggregation is hypothesised to be toxic and may cause the loss of normal FHL1 function during muscle differentiation. To deter- mine how FHL1 mutations lead to aggregation and cause myopathy, dif- ferent FHL1 mutants representative of each disease and mutation type were over-expressed in C2C12 myoblasts as they differentiated to form myotubes. Protein aggregation was assessed by immunofluorescence and Western blot and of FHL1 together with markers for protein aggregation and Menadione-NBT staining for reducing bodies, which are clinically specific to RBM. Myotube differentiation was assessed by immunofluores- cence and Western blot of myogenin and myosin heavy chain (MHC). Although protein aggregation is only clinically associated with RBM we show other FHL1 mutations reported in SPM and XMPMA also lead to aggregate formation in C2C12 myotubes in a time dependant manor. These aggregates contained markers observed in RBM patient biopsies including ubiquitin and GRP78, and were positive for Menadione-NBT staining. Wild-type FHL1 did not aggregate and had a similar level of expression compared to the FHL1 mutants. This study suggests that aggregation may be a common hallmark of FHL1 myopathies and that these diseases may potentially share some common pathological mechanisms. http://dx.doi:10.1016/j.nmd.2012.06.325 G.P.120 FHL1-related Reducing Body Myopathy and Emery–Dreifuss muscular dystrophy: A comparative histoenzymological, immunohistochemical and ultrastructural study E. Malfatti 1 , M. Olive ´ 2 , A.L. Taratuto 3 , P. Richard 4 , M. Bitoun 5 , G. Brochier 6 , P. Lafore ˆt 7 , T. Stojkovic 7 , M. Alexianu 8 , T. Maisonobe 9 , M. Saccoliti 3 , B. Prudhon 5 , E. Lace `ne 6 , B. Eymard 7 , M. Fardeau 6 , G. Bonne 5 , N.B. Romero 10 1 Institut of myology, Department of Neurological, Neurosurgical, and Behavioral Sciences, University of Siena, Inserm U974 – CNR, Unite ´ de Morphologie Neuromusculaire, Paris, France; 2 Institut of myology, Institut de Neuropatologia, IDIBELL-Hospital de Bellvitge, Unite ´ de Morphologie Neuromusculaire, Institut de Myologie, Barcelona, Spain; 3 Hospital Nac- ional de Pediatrı ´a J.P Garrahan, Instituto de Investigaciones Neurologicas, FLENI, Buenos Aires, Argentina; 4 AP-HP, GHU La Pitie ´-Salpe ˆtrie `re, U.F. Cardioge ´ne ´tique et Myoge ´ne ´tique, Service de Biochimie Me ´ tabolique, Paris, France; 5 Inserm U974 – CNRS-UMR7215 UPMC-Paris 6 UM76, GHU La Pitie ´-Salpe ˆtrie `re, Paris, France; 6 Unite ´ de Morphologie Neuro- musculaire, Institut de Myologie, Groupe Hospitalier Universitaire La Pitie ´- Salpe ˆtrie `re, Paris, France; 7 Centre de re ´fe ´rence de Pathologie Neuromus- culaire Paris-Est, Institut de Myologie, GHU Pitie ´-Salpe ˆtrie `re, Assistance Publique-H, Paris, France; 8 Bucarest University Hospital, Bucarest, Romania; 9 De ´partement de Neurophysiologie Clinique, Assistance Publiq- ue-Ho ˆ pitaux de Paris, GHU La Pitie ´-Salpe ˆtrie ` re, Paris, France; 10 Unite ´ de Morphologie Neuromusculaire, Institut de Myologie, Groupe Hospitalier Universitaire La Pitie ´-Salpe ˆtrie `re, Inserm U974 – CNRS-UMR7215 UPMC-Paris 6 UM76, Centre de re ´fe ´rence de Pathologie Neuromusculaire, Paris, France FHL1-related myopathies are rare disorders that recently emerged and include reducing body myopathy (RBM) a congenital disorder defined by the presence of cytoplasmic inclusions revealed by menadione-NBT stain- ing, and Emery–Dreifuss muscular dystrophy (EDMD) characterized by early joint contractures, muscular dystrophy and cardiac involvement with arrhythmias. We report the muscle biopsy features in a series of 13 patients suffering from RBM (9) and EDMD (4) with mutations in FHL1 gene, emphasizing unusual morphological characteristics. A sum- mary of the clinical examination was performed. Muscle specimens were processed for histoenzymological, immunohistochemical and ultrastruc- tural analysis. Molecular analysis was accomplished by sequencing the coding regions of FHL1 gene. Muscle biopsies from RBM patients showed marked variation of fiber size, increased number of internal nuclei, fibro- fatty tissue proliferation and type I fiber predominance. A sectorial distri- bution of lesions was observed. Several fibers contained large inclusions strongly reacting with menadione-NBT. Desmin, alphaB-crystallin and myotilin immunoreactivity was observed surrounding RB but not within them. At the ultrastructural level, reducing bodies and cytoplasmic bodies were observed in all muscle biopsies. Furthermore a dense granular mate- rial was usually found in the subsarcolemmal region and between the myo- fibrils; surprisingly this was frequently seen around the myonuclei and associated to cytoplasmic bodies. By contrast, no reducing bodies were found in EDMD and the lesions were minimal. Molecular analysis revealed missense mutations in the 2nd FHL1 LIM domain for the RBM patients and ins/del or missense mutations affecting the 4th FHL1 LIM domain for EDMD patients. Our findings expand the morphological features of reducing body myopathy and further illustrate major morpho- logical differences between patients carrying mutations in the 2nd or in the 4th LIM domain of FHL1. http://dx.doi:10.1016/j.nmd.2012.06.326 G.P.121 X-linked recessive distal myopathy with hypertrophic cardiomyopathy caused by a novel mutation in the FHL1 gene C.E. D’Arcy 1 , V. Kanellakis 2 , M.M. Ryan 3 , C.A. McLean 1 1 The Alfred Hospital, Department of Anatomical Pathology, Melbourne, Australia; 2 University of Melbourne, Applied Genetics Diagnostics, Mel- bourne, Australia; 3 Royal Children’s Hospital, Neurosciences Department, Melbourne, Australia The four and a half LIM domain protein 1 (FHL1) gene encodes FHL1, a LIM domain containing protein that regulates skeletal and cardiac muscle function. FHL1 mutations are associated with variable phenotypes includ- ing reducing body myopathy, X-linked myopathy with postural muscle atrophy, scapuloperoneal myopathy and Emery–Dreifuss muscular dystro- phy. The FHL1 gene encodes three FHL1 isoforms (FHL1A, FHL1B, FHL1C). Patients with FHL1 mutations affecting all three isoforms exhibit a more severe phenotype, whereas mutations that affect only FHL1A are less severe. We describe a boy with a family history consistent with X-linked 902 Abstracts / Neuromuscular Disorders 22 (2012) 804–908