[Facioscapulohumeral muscular dystrophy. The spectrum of clinical manifestations and molecular genetic changes].

Although the gene for facioscapulohumeral muscular dystrophy (FSHD) has not been identified so far, 4q35 deletion represents a diagnostic marker of the disease. In the present study, 46 consecutive symptomatic patients with 4q35 FSHD deletions or typical FSHD clinical features were evaluated. The patients were divided into three groups: 33 patients (72%) with typical FSHD phenotype and 4q35 FSHD deletion, eight (17%) with atypical (non-Landouzy-Dejerine) FSHD phenotype but with 4q35 FSHD deletion, and five patients (11%) with the typical FSHD phenotype but without FSHD 4q35 deletion. Apparently, the 4q35 deletion is associated not only with Landouzy-Dejerine FSHD but also with a variety of "atypical" FSHD forms. On the other hand, the Landouzy-Dejerine FSHD phenotype is possibly a polyetiological syndrome caused in some patients by other genetic effects than 4q35 deletion.