BRCA1 and acquired polycythemia vera: New UK guidance from the National Screening Committee will allow screening in BRCA1/2 PV carriers once their 10 year risk is 8%.24 This level of risk is estimated in BRCA1 PV carriers aged 25 years with a first degree relative diagnosed <40 years in both the Tyrer-Cuzick and BOADICEA models.25 26 Many other countries already offer screening in BRCA1/2 PV carriers from 25 years.