A decade's progress in
facioscapulohumeral muscular dystrophy genetics has been marked by the discovery of novel genetic phenomena such as crossover of subtelomeric
DNA between chromosomes 4 and 10 in normal individuals and by the recognition that the
facioscapulohumeral muscular dystrophy deletion-mutation may cause a position variegation effect on more proximal
DNA. The mutated
DNA itself is probably not transcribed. Larger deletions tend to cause more severe disease. Antenatal diagnosis, based on detection of the short fragment of mutated
DNA, is possible in between 95 and 100% of cases, depending on the precise nature of the parental
facioscapulohumeral muscular dystrophy mutation. Yet remarkably, the nature of the gene product(s) of the affected proximal gene(s), as well as of the molecular pathogenesis of
facioscapulohumeral muscular dystrophy muscle,
retinal and
cochlear disease, is completely unknown. Marked perivascular
inflammation is often present in
facioscapulohumeral muscular dystrophy muscle biopsies. The expression of
facioscapulohumeral muscular dystrophy within reported monozygotic twinships differs greatly. This raises the question of whether variations in expression of the T-cell receptor gene repertoire or of other immune genes play an important modifying role in determining the severity of
facioscapulohumeral muscular dystrophy. A focus on traditional scientific disciplines may now be appropriate. Symptomatic treatments, for instance of scapular winging and of
lagophthalmos, are important, and timely
photocoagulation of the
retinal exudates which are a very rare, but real, complication of
retinal telangiectasis can curtail visual loss. The results of collobarative trials of pharmacological agents such as
albuterol which affect muscle mass and development are awaited.