IMMUNODETECTION ANALYSIS OF MUSCULAR DYSTROPHIES IN MEXICO BENJAMI ´ N GO ´ MEZ-DI ´ AZ, MSc, 1 HAYDEE ´ ROSAS-VARGAS, PhD, 2 BLADIMIR ROQUE-RAMI ´ REZ, BSc, 3 PEDRO MEZA-ESPINOZA, MSc, 2 LUIS A. RUANO-CALDERO ´ N, MD, 4 FRANCISCA FERNA ´ NDEZ-VALVERDE, BSc, 5 DEYANIRA ESCALANTE-BAUTISTA, BSc, 3 ROSA E. ESCOBAR-CEDILLO, MD, 6 LAURA SA ´ NCHEZ-CHAPUL, PhD, 7 STEVEN VARGAS-CAN ˜ AS, MD, 5 LUZ B. LO ´ PEZ-HERNA ´ NDEZ, PhD, 3 ELIGANTY BAHENA-MARTI ´ NEZ, MD, 3 ALEXANDRA B. LUNA-ANGULO, BSc, 2 PATRICIA CANTO, PhD, 3 and RAMO ´ N M. CORAL-VA ´ ZQUEZ, PhD 8 1 Departamento de Morfologı ´a Celular y Molecular, Instituto Nacional de Rehabilitacio ´n, Secretarı ´a de Salud, Mexico City, M exico 2 Unidad de Investigacio ´n M edica en Gen etica Humana, Hospital de Pediatrı ´a, Centro M edico Nacional Siglo XXI-IMSS, Mexico City, M exico 3 Divisio ´n de Investigacio ´n Biom edica, Subdireccio ´n de Ensen ˜anza e Investigacio ´n, Centro M edico Nacional 20 de Noviembre, ISSSTE, Mexico City, M exico 4 Hospital General de Durango, Durango, M exico 5 Departamento de Patologı ´a Experimental, Instituto Nacional de Neurologı ´a y Neurocirugı ´a Manuel Velasco Sua ´rez, Mexico City, M exico 6 Servicio de Electrodiagno ´stico, Instituto Nacional de Rehabilitacio ´ n, Secretarı ´a de Salud, Mexico City, M exico 7 Laboratorio de Bioquı ´mica Muscular, Instituto Nacional de Rehabilitacio ´n, Secretarı ´a de Salud, Mexico City, M exico 8 Seccio ´n de Posgrado, Escuela Superior de Medicina, Instituto Polit ecnico Nacional, Col. Casco de Santo Tomas, Del. Miguel Hidalgo, CP 11340, Mexico City & Subdireccio ´n de Ensen ˜anza e Investigacio ´n, Centro M edico Nacional 20 de Noviembre, ISSSTE, Mexico City, M exico Accepted 27 September 2011 ABSTRACT: Introduction: The muscular dystrophies (MDs) result from perturbations in the myofibers. These alterations are induced in part by mechanical stress due to membrane cell fra- gility, disturbances in mechanotransduction pathways, muscle cell physiology, and metabolism. Methods: We analyzed 290 biopsies of patients with a clinical diagnosis of muscular dystro- phy. Using immunofluorescence staining, we searched for pri- mary and secondary deficiencies of 12 different proteins, including membrane, costamere, cytoskeletal, and nuclear pro- teins. In addition, we analyzed calpain-3 by immunoblot. Results: We identified 212 patients with varying degrees of pro- tein deficiencies, including dystrophin, sarcoglycans, dysferlin, caveolin-3, calpain-3, emerin, and merosin. Moreover, 78 biop- sies showed normal expression of all investigated muscle pro- teins. The frequency rates of protein deficiencies were as follows: 52.36% dystrophinopathies; 18.40% dysferlinopathies; 14.15% sarcoglycanopathies; 11.32% calpainopathies; 1.89% merosinopathies; 1.42% caveolinopathies; and 0.47% emerino- pathies. Deficiencies in lamin A/C and telethonin were not detected. Conclusion: We have described the frequency of common muscular dystrophies in Mexico. Muscle Nerve 45: 338–345, 2012 Muscular dystrophies (MDs) are a group of defined pathologic entities characterized by vari- able degrees and distribution of muscle wasting and weakness. 1 Currently, these account for about 50 diseases. 2 MDs are usually classified according to age at onset, pattern of inheritance, and group of muscles involved. Diagnosis represents a chal- lenge, because in many cases phenotypical features may resemble more than one type of MD, and clin- ical overlap may occur, with serious implications for genetic counseling. 3,4 Patterns of muscle involvement may reflect dif- ferent roles of muscle proteins (Table 1) under mechanical stress. Proximal muscle groups that contain larger fibers bear more weight and are those first affected. 5 These are frequently related to the loss of sarcolemmal integrity (e.g., dystro- phinopathies or sarcoglycanopathies). Sarcomeric proteins (e.g., telethonin, titin, and myotilin) are more involved in distal MDs. 6 Nevertheless, with age, weakness affects more muscles and becomes generalized, leading to disability in most cases. Many other proteins participate in the pathophysi- ology of MDs. Extracellular matrix proteins, such as a2-laminin (merosin), play an important role in lateral transmission of contractile force to the base- ment membrane. 7 Nuclear envelope proteins (emerin and lamin A/C) are important for the connection between nucleoskeleton and cytoskele- ton via the LINC complex (linker of nucleoskele- ton and cytoskeleton), which is comprised of nesprins, sun, and lamin proteins. 8 Finally, the fol- lowing proteins are associated with aberrant glyco- sylation: protein-O-mannosyl transferase 1, protein- O-mannosyl transferase 2, protein-O-mannose 1,2- N-acetylglucosaminyltransferase 1, fukutin, fukutin- related protein, and like-acetylglucosaminyltrans- ferase (LARGE). Furthermore, those proteins involved in maintenance of the structure of sarco- plasmic reticulum (obscurin) may also play a role in MDs. 9,10 The frequency of subtypes of MDs may differ among populations. Limb-girdle muscular Abbreviations: BMD, Becker muscular dystrophy; BPB, bromophenol blue; Cav-3, caveolin-3; CK, creatine kinase; CMD, congenital muscular dystrophy; DMD, Duchenne muscular dystrophy/dystrophin; DTT, dithio- threitol; EMD, emerin; FKRP, fukutin-related protein; FKTN, fukutin; IMSS, Instituto Mexicano del Seguro Social; LARGE, acetylglucosaminyltransfer- ase-like protein; LGMD, limb-girdle muscular dystrophy; LINC complex, linker of nucleoskeleton and cytoskeleton; LMNA, lamin A/C; MD, muscu- lar dystrophy; MDC1A, muscular dystrophy congenital type 1A; PBS, phosphate-buffered saline; SG, sarcoglycan Correspondence to: R. M. Coral-Va ´ zquez; e-mail: rmcoralv@gmail.com V C 2011 Wiley Periodicals, Inc. Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/mus.22314 Key words: calpainopathies, dysferlinopathies, dystrophinopathies, immunofluorescence, muscular dystrophy 338 Muscular Dystrophies in Mexico MUSCLE & NERVE March 2012