Hairy cell leukemia in three siblings: an apparent HLA-linked disease

In a sibship of 11 adults the HLA haplotype A1, B7 occurred in four brothers, three of whom developed hairy cell leukemia (HCL) within a seven-year period. While this haplotype does not appear to occur with increased frequency in random cases of HCL, the fact that three cases of this uncommon and unique disorder occurred within one family and affected siblings with a common haplotype strongly suggests a genetic linkage.