Sporadic late-onset nemaline myopathy: clinical spectrum, survival and treatment outcomes

OBJECTIVES: To describe the clinical phenotype, long-term treatment outcome and overall survival of sporadic late onset nemaline myopathy (SLONM) with or without a monoclonal protein (MP).
METHODS: we conducted a retrospective chart review of patients seen between September 2000 and June 2017 and collected clinical, laboratory and survival data. Treatment response was classified as mild, moderate, or marked as adjudged by predefined criteria.
RESULTS: We identified 28 patients with SLONM, 17 (61%) had an associated MP. Median age at symptom onset was 62 years. Diagnosis was often delayed by a median of 35 months from symptom onset. There was no difference in clinical or laboratory features between patients with or without MP. Although the majority of patients had proximal or axial weakness at onset, about 18% of patients had atypical presentations. 7/9 (78%) patients receiving intravenous immunoglobulin (IVIG), 6/8 (75%) receiving hematologic therapy as either autologous stem cell t...