To the Editor: Myelodysplastic neoplasms (MDS) are hematopoietic stem cell disorders characterized by ineffective hematopoiesis and dysplastic cells in the bone marrow (BM) [1]. In addition, patients with MDS display an increased susceptibility to osteoporosis [2]. Evidence points towards dysregulation in the BM niche that concurrently impairs bone turnover and hematopoiesis. We identified fibroblast growth factor (FGF)-23 as a critical regulator of bone mineralization and erythropoiesis.