Respiratory function in facioscapulohumeral muscular dystrophy 1

To test the hypothesis that wheelchair dependency and (kypho-)scoliosis are risk factors for developing respiratory insufficiency in facioscapulohumeral muscular dystrophy, we examined 81 patients with facioscapulohumeral muscular dystrophy 1 of varying degrees of severity ranging from ambulatory patients to wheelchair-bound patients. We examined the patients neurologically and by conducting pulmonary function tests: Forced Vital Capacity, Forced Expiratory Volume in 1 second, and static maximal inspiratory and expiratory mouth pressures. We did not find pulmonary function test abnormalities in ambulant facioscapulohumeral muscular dystrophy patients. Even though none of the patients complained of respiratory dysfunction, mild to severe respiratory insufficiency was found in more than one third of the wheelchair-dependent patients. Maximal inspiratory pressures and maximal expiratory pressures were decreased in most patients, with a trend that maximal expiratory pressures were more affected than maximal inspiratory pressures. Wheelchair-dependent patients with (kypho-)scoliosis showed the most restricted lung function. Wheelchair-dependent patients with (kypho-)scoliosis are at risk for developing respiratory function impairment. We advise examining this group of facioscapulohumeral muscular dystrophy patients periodically, even in the absence of symptoms of respiratory insufficiency, given its frequency and impact on daily life and the therapeutic consequences.