CXCR4 and WHIM syndrome: Remarkably, long-term remission from WHIM syndrome, caused by GoF variants in CXCR4, was seen in an adult who had undergone chromothripsis of chromosome 2 resulting in deletion of the disease allele in a single hematopoietic stem cell, leading to the repopulation of the bone marrow with the haploinsufficient CXCR4 cells (McDermott et al., 2015; Heusinkveld et al., 2017).