Objective: Sporadic late-onset nemaline myopathy (SLONM) is a rare, late-onset myopathy that progresses subacutely. If associated with a monoclonal gammopathy of unknown significance (MGUS), the outcome is unfavorable: the majority of these patients die within 1 to 5 years of respiratory failure. This study aims to qualitatively assess the long-term treatment effect of high-dose melphalan (HDM) followed by autologous stem cell transplantation (SCT) in a series of 8 patients with SLONM-MGUS.Methods: We performed a retrospective case series study (n 5 8) on the long-term (1-8 years) treatment effect of HDM followed by autologous SCT (HDM-SCT) on survival, muscle strength, and functional capacities.