Insulin-like Growth Factor Binding Protein-3 (IGFBP3) Induces Fetal Hemoglobin in Hematopoietic Stem and Progenitor Cells from Patients with Sickle Cell Anemia

Background: Fetal hemoglobin (HbF, α2g2) induction is known to reduce the clinical complications of sickle cell anemia (SCA). Progress in identifying novel HbF inducing strategies has been slowed by an incomplete understanding of gamma-globin regulation. We have used natural genetic variation to identify novel genes and pathways associated with HbF levels in patients with SCA, beginning with whole exome sequencing (WES). This approach identified FOXO3, a transcription factor important for insulin signaling and erythroid maturation, among other functions, as a positive regulator of HbF. We then confirmed the role of FOXO3 in HbF regulation with functional studies in erythroid culture (Zhang, Blood 2018). To overcome the limitations of WES, namely the absence of regulatory and promotor sequencing data, we performed whole genome sequencing (WGS) on 658 pediatric SCA patients, and analyzed the data for common variants predictive of HbF levels.