A novel autosomal dominant limb-girdle muscular dystrophy (LGMD 1F) maps to 7q32.1-32.2 L. Palenzuela, PhD; A.L. Andreu, MD, PhD; J. Gàmez, MD, PhD; M.R. Vilà, PhD; T. Kunimatsu, PhD; A. Meseguer, PhD; C. Cervera, MD, PhD; I. Fernandez Cadenas, MSc; P.F.M. van der Ven, PhD; T.G. Nygaard, MD; E. Bonilla, MD; and M. Hirano, MD Abstract—In 2001, the authors described the clinical features of a genetically distinct autosomal dominant limb-girdle muscular dystrophy (LGMD; LGMD 1F). Using a genome-wide screen with more than 400 microsatellite markers, the authors identified a novel LGMD disease locus at chromosome 7q32.1-32.2. Within this chromosomal region, filamin C,a gene encoding actin binding protein highly expressed in muscle, was an obvious candidate gene; however, the authors did not detect any defects in filamin C or its protein product. NEUROLOGY 2003;61:404 –406 The limb-girdle muscular dystrophies (LGMD) com- prise a heterogeneous group of hereditary diseases characterized by progressive and predominantly proxi- mal muscle weakness with histologic signs of necrosis and regeneration in muscle. To date, 15 genetically distinct forms of LGMD have been identified. 1-3 Two years ago, we described the clinical, histo- logic, and genetic features of a large Spanish kindred spanning five generations with LGMD and apparent autosomal dominant (AD) inheritance; 44 of 76 (58%) children of affected parents manifested the disease. Clinical examination of 61 persons showed progres- sive muscle weakness in 32, affecting mainly the muscles of the pelvic and shoulder girdles. 4 Molecu- lar genetic linkage analyses to screen chromosomal loci associated with other forms of AD-LGMD dem- onstrated that the kindred has a genetically distinct form of AD-LGMD. 4 To localize the chromosomal lo- cus of the disease, we undertook a genome-wide scan using microsatellite markers. Methods. Peripheral blood was obtained from 47 persons (27 affected and 20 unaffected) with informed consent, and DNA was extracted using the salting-out method. 5 Genome-wide screening was performed with 400 polymorphic microsatellite markers spaced throughout the 22 autosomal chro- mosomes in a subset of the kindred containing 15 persons using the GeneScan Analysis 2.1 and Genotyper 2.1 software (Perkin- Elmer Applied Biosystems Inc, Foster City, CA). Parametric two- point linkage analysis for each marker was performed using the FASTLINK (version 4.0, Anthem, Arizona) software package. 6 The disease was considered AD with a 90% penetrance. The disease gene frequency was estimated at 1/100,000. Marker allele fre- quencies were estimated by allele counting of all genotyped persons. After genome-wide screening with fluorescently labeled mark- ers, additional P 32 -dATP end-labeled markers (Human MapPairs, Invitrogen, Carlsbad, CA) adjacent to uninformative fluorescent markers were screened using previously described methodology. 7 After obtaining a weakly positive lod score of 0.61 with marker D7S680, fine mapping was carried out with 13 additional radioac- tively labeled markers in the 9.4 cM region of chromosome 7 bounded by and immediately flanking D7S530 and D7640 using DNA from the 47 available family members. We amplified and sequenced the entire coding region of the filamin C gene (FLNC or FLN2 [GenBank accession number AF252549]) and its untranslated regions and more than 1000 bases of the promoter region. To screen for a possible alteration in the splicing of FLNC, the entire 8.3 Kb cDNA was sequenced. Southern blot analyses were performed to exclude any large-scale rearrangements in the FLNC gene, and Northern blot analyses were performed to screen for alterations in the amount or integ- rity of the FLNC messenger RNA. To assess FLNC protein, West- ern blot immunoanalyses were performed using a monoclonal anti-filamin C antibody. 8 Results. Linkage analysis of the 13 markers on chromo- some 7 revealed 11 with lod scores 3 (table) that linked the disease to chromosome 7q32.1–32.2. The maximum two-point lod score value was 7.56 at = 0 with marker D7S2544. We were able to accurately define the final criti- cal region and established a common disease haplotype in Additional material related to this article can be found on the Neurology Web site. Go to www.neurology.org and scroll down the Table of Con- tents for the August 12 issue to find the title link for this article. From the Centre d’Investigacions en Bioquímica i Biologia Molecular (CIBBIM) (Drs. Palenzuela, Andreu, and Meseguer, I. Fernandez Cadenas), Hospital Universitari Vall d’Hebron, Barcelona, Spain; Servei de Neurologia (Drs. Gàmez and Cervera), Hospital Universitari Vall d’Hebron, Barcelona, Spain; Department of Neurology (Drs. Vilà, Kunimatsu, Bonilla, and Hirano), Columbia University College of Physicians and Surgeons, New York, NY; Department of Cell Biology (Dr. van der Ven), University of Potsdam, Germany; and Department of Neurology (Dr. Nygaard), University of Medicine and Dentistry New Jersey Medical School, Newark, NJ. Drs. Palenzuela and Andreu contributed equally to this work. Supported by grants from the NIH (R01-AR47989) and the Spanish Ministry of Science and Technology (SAF 2001–1998). Received January 29, 2003. Accepted in final form April 11, 2003. Address correspondence and reprint requests to Dr. Michio Hirano, Associate Professor of Neurology, Columbia-Presbyterian Medical Center, 630 West 168th Street, P&S 4-443, New York, NY 10032; e-mail: mh29@columbia.edu 404 Copyright © 2003 by AAN Enterprises, Inc.