S.P.29 Respiratory dysfunction of dysferlinopathy

Abstract

<h2>Abstract</h2> Dysferlinopathy is an autosomal recessive muscular dystrophy caused by <i>DYSF</i> mutations. There are two major phenotypes of dysferlinopathy, proximal dominant limb-girdle muscular dystrophy (LGMD) 2B and distal dominant Miyoshi myopathy (MM). Respiratory dysfunction has been rarely reported in dysferlinopathy patients. <i>Objective:</i> To examine the respiratory function in patients with dysferlinopathy. We retrospectively reviewed the respiratory function (% forced vital capacity [FVC]) for 27 dysferlinopathy patients confirmed by genetic analysis and/or immunohistochemical staining in our hospital. The mean age at the onset was 22.8±8.5 (range 10–46years). Of 27 patients, LGMD2B, MM, and unclassified were 13, 13, and 1, respectively. Serum CK level was 5171±3005 (range 192–12,671IU/l). Twenty-one patients were still ambulant and four were wheelchair-bound. The %FVC was 99.0±29.1 (range, 15.3–131.0). In three (11.1%) patients, %FVC was <80% (23.9–41.4%) and two patients used non-invasive positive pressure ventilation. The average %FVC of patients within 25years from the onset was 108.8±13.5% (<i>n</i>=19), while 68.2±43.6% (<i>n</i>=8) in patients over 25years and 109.5±12.3% in ambulatory patients (<i>n</i>=21), while 43.3±28.9% in wheelchair-bound (<i>n</i>=4). The Linear regression analysis to determine the relationship between %FVC and other clinical parameters revealed the age (<i>p</i>=0.004), the duration from the onset to present (<i>p</i>=0.003), and the CK (<i>p</i>= 0.009) as to be significantly correlated with %FVC. There was no significant difference in %FVC of LGMD2B and MM. Dysferlinopathy can cause severe respiratory failure. Respiratory dysfunction in patients with dysferlinopathy, which is characterized by long disease duration and advanced weakness and muscle atrophy, should be carefully monitored.