Mutations in the Nxf1 gene cause lymphopenia and thrombocytopenia. (A) Peripheral blood platelets count from 7-week-old G1 offspring of N-ethyl-N-nitrosurea–mutagenised BALB/c males. (B) Position of amino acid substitutions on the Nxf1 protein. (C) Automated analysis of platelet and lymphocyte counts in Nxf1^C587R/+ mice and WT littermate controls. (D) Average decrease in the hematopoietic population. (E) The C587R phenotype is BM-derived. Platelet and lymphocyte counts in lethally irradiated WT recipients reconstituted with C587R/+ or littermate control BM (top). Cell counts in lethally irradiated C587R/+ and control recipients reconstituted with WT BM (bottom). Circles and triangles represent cell counts for an individual mouse. Data show mean with standard deviation (SD). **P < .01; ****P < .0001. LRR, leucine-rich repeat; NS, nonsignificant; NTF2, nuclear transport factor 2–like domain; Plt, platelet; RBD, RNA-binding domain; UBA, ubiquitin-associated–like domain.