Additionally, approximately 2.6% of pediatric B-ALL patients have a rearrangement in PAX5 that fuses it to other genes,[31,32,35,43] causing B-cell development to be blocked, as seen in PAX5-ETV6 and PAX5-FOXP1 fusions. The gene discussed is FOXP1; the disease is precursor B-cell acute lymphoblastic leukemia.