Data from: 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 transplant (ASCT), or chemotherapy and 1/8 (13%) receiving
immunosuppressive therapies responded to treatment (p=0.001). All 3
patients with marked response were treated with IVIG, 2 of them had a MP.
The 5-year and 10-year overall survivals from symptom onset were 92% and
68% respectively, with no difference between patients with or without MP.
CONCLUSIONS: SLONM has a wide spectrum of clinical presentations. In this
contemporary case series, overall survival of patients did not seem to be
affected by the presence of a MP. Initial treatment with IVIG is
reasonable in all patients, followed by ASCT or chemotherapy as
second-line therapy in patients with an associated MP.