PV prevalence was as follows: BRCA1, n = 34, 0.26%; BRCA2, n = 62, 0.48%; ATM, n = 65, 0.50%; CHEK2, n = 93, 0.72%; and PALB2, n = 33, 0.25%. Here, CHEK2 is linked to acquired polycythemia vera.