FACIOSCAPULOHUMERAL MUSCULAR-DYSTROPHY (FSHD) - DESIGN OF NATURAL-HISTORY STUDY AND RESULTS OF BASE-LINE TESTING

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant disorder with a characteristic distribution of weakness and variable severity. Prospective, longitudinal data on FSHD are essential for the design of therapeutic trials and in assessment of genetic heterogenei ty. We enrolled 32 well-defined FSHD patients and 32 normal subjects i n a natural history study of FSHD. All subjects underwent baseline qua ntitative muscle testing (QMT), manual muscle testing (MMT), and funct ional testing. QMT demonstrated substantial weakness in muscles usuall y spared in FSHD. Major right/left side-to-side differences in strengt h were documented but, unexpectedly, were not related to handedness. U sing the QMT data on normal subjects, we developed regression models r elating strength to age, gender, and height and used these models to s tandardize QMT measurements in FSHD patients, expressing them as the n umber of SDs from average normal performance. This model-based strateg y should facilitate the construction of composite scores to describe t he natural history of FSHD and could be useful for constructing sensit ive measures of progression in other neuromuscular diseases.