An inherited 4q35-EcoRI-DNA-fragment of 35 kb in a family with a sporadic case of facioscapulohumeral muscular dystrophy (FSHD).

We present a case of an adult male patient showing clinical, neurophysiological and histological signs consistent with the phenotype of facioscapulohumeral muscular dystrophy. On molecular testing with a 4q35-DNA-probe p13E-11 (D4F104S1), the patient, his clinically unaffected mother and two sisters shared a 4q35-EcoRI-DNA-fragment of 35 kb on the transition between FSHD1A-associated and polymorphic fragments. Explanatory hypotheses, such as reduced penetrance in females or a phenotype unlinked to the 4q35-locus are considered. Alternatively, additional changes in the unidentified FSHD1A gene could have caused the phenotype. Thus, in such rare cases, the diagnostic evidence of 4q35-EcoRI-fragments is still limited.