CXCR4 and Decreased total leukocyte count: Identified at the NIH as patient WHIM-09, this patient spontaneously cured leukopenia and susceptibility to infectious diseases, due to a chromothripsis event in chromosome 2 of presumably a single hematopoietic progenitor cell, which eliminated the Cxcr4R334X allele along with 163 other genes and switched a hyper-responsive for an haploinsufficient CXCR4 state (148).