Reader response: Sporadic late-onset nemaline myopathy: Clinical spectrum, survival, and treatment outcomes

We read with interest the article by Naddaf et al.1 on their experience with sporadic late-onset nemaline myopathy (SLONM). The authors' conclusion was that IV immunoglobulin (IVIg) should be offered as a first-line treatment for patients with SLONM. We have 2 comments regarding this statement. First, the degree of weakness and disability in patients who received IVIg vs those who received autologous stem cell transplantation (SCT) should be clarified. Is it possible that the patients who received IVIg had milder disease resulting in a selection bias? In the past few years, we have treated several patients with SLONM associated with monoclonal protein (MP) who had severe phenotype with IVIG. Initially, their disease appeared to be stable over a 6-month period (unclear if this was related to IVIG or not). Unfortunately, most patients had rapid deterioration of their disease and decline in their pulmonary function. By the time SCT was considered as second-line therapy, they were deemed too weak for SCT and eventually died. Is it possible that the authors are biased by seeing mainly patients who are healthy enough to be able to travel and be seen at the Mayo Clinic?