Duchenne muscular dystrophy (DMD) is a debilitating X-linked muscle disease. We have used sequence information from complementary DNA clones, derived from the gene that is deleted in DMD patients, to generate an antiserum that stains the surface membrane of intact human and mouse skeletal muscle, but not that of DMD patients and mdx mice. Here we identify the protein reacting with this antiserum as a single component of relative molecular mass 210,000 (Mr = 210K) that fractionates with a low-ionic strength extract of intact human and mouse skeletal muscle. It is therefore distinct from the 400 K protein found in the heavy microsomal fraction of normal muscle and identified as a putative product of the DMD gene. We also analyse further the disease specificity of the antiserum. Positive staining is seen in normal controls, and in samples from patients with a wide range of muscular dystrophies other than DMD. Becker muscular dystrophy, which is allelically related to DMD, was the only other exception, and gave a sporadic staining pattern. The demonstration of a specific defect in the surface membrane of DMD muscle fibres substantiates the hypothesis that membrane lesions may initiate muscle degradation in DMD.

To investigate the nature of the inflammatory response in facioscapulohumeral muscular dystrophy (FSHD), we analyzed mononuclear cells in muscle sections obtained from 18 FSHD patients and 8 controls. Monoclonal antibodies reactive for T cells, T cell subsets, B cells, and NK cells were used for cell typing. Macrophages were identified by acid phosphatase reaction. The localization of perforin, granzyme A, MHC-I and -II, dystrophin, and alpha-actinin antigens was also examined. We found that all FSHD patients, both familiar and sporadic cases, had greater amounts of mononuclear cellular infiltrates in muscle than controls, in whose specimens only few extra vascular mononuclear cells were counted. Seventy-two percent (13 of 18) of the patients had more than 50 inflammatory mononuclear cells per 1000 muscle fibers, and 33% (6 of 18) patients had numerous inflammatory cells exceeding 600 per 1000 muscle fibers (1835 +/- 482 SE). Nonnecrotic fibers invaded by mononuclear cells with either T8+, perforin+, or granzyme A+ were not observed in FSHD, while a few degenerating fibers were superficially invaded by T cells and macrophages. Occasional T cells were observed moving through the blood vessel wall. The increased number of necrotic fibers was paralleled by an increased number of inflammatory cells (r = 0.783, P = 0.0001). Genetic analysis, using the probes p13E-11, pFR-1, D4S139, and D4S163, was done in 6 patients (3 familiar, 3 sporadic) who had numerous inflammatory infiltrates. These 6 patients had small (< 28 kb) EcoRI fragments associated with the disease, and the disease was linked to 4q35. These results suggest that, in chromosome 4-linked FSHD: (1) inflammatory changes in muscle are a common histological feature; (2) mononuclear cellular infiltrates may enhance muscle fiber damage; but (3) T-cell-mediated cytotoxicity directed against muscle fibers is unlikely. We speculate that the immune effector mechanism in FSHD is different from that in previously reported inflammatory myopathies and Duchenne muscular dystrophy.

The current findings suggest a critical role for fukutin gene mutation in the loss or modification of glycosylation of the extracellular peripheral membrane protein, alpha-dystroglycan, which may cause a crucial disruption of the transmembranous molecular linkage of muscle fibers in patients with FCMD.

Fukuyama type congenital muscular dystrophy (FCMD) is an autosomal recessive severe muscular dystrophy associated with an anomaly of the brain. Twenty-one FCMD families, 13 of them with consanguineous marriages, were analysed by genetic linkage analyses with polymorphic microsatellite markers to map the FCMD gene. Significant lod scores were obtained with the markers D9S58 (Zmax = 5.81 at theta = 0.06), D9S59 (Zmax = 4.33 at theta = 0.02), and HXB (Zmax = 3.28 at theta = 0.09) on chromosome 9q31-33. Multipoint analysis placed FCMD between D9S58 and D9S59, with a maximum lod score of 16.93. These markers will be useful for presymptomatic, prenatal and carrier diagnosis of family members carrying FCMD, and they represent important resources for the identification of a gene responsible for FCMD.

Because oropharyngeal dysphagia in DMD was evident in teenage patients as well as those without clinical symptoms, VF is recommended in patients with DMD.