MPDs: it's all in the family

摘要

Dameshek was wrong. In this issue of Blood, in a landmark epidemiologic study, Landgren and colleagues demonstrate that first-degree relatives (parents, siblings, and offspring) of Swedish myeloproliferative disorder (MPD) patients have a 5- to 7-fold increased risk of developing an MPD.Onee thought to be rare and mainly reportable as such, a Polycythemia Vera Study Group (PVSG) analysis of 652 polycythemia vera (PV) patients found 5 with similarly affected parents, suggesting the possibility of familial PV.Gilbert was the first to challenge the perception that MPDs in general were random in occurrence and that familial MPD was rare. From the literature and a survey of MPD patients, she was able to collect 42 families in which an MPD occurred in up to 3 generations, and in 50% of the pedigrees more than one type of MPD was represented. In a more recent survey of 458 MPD patients, 35 families with at least 2 affected members were identified, a prevalence of 7.6%, and the frequencies were similar for PV (8.7%), essential thrombocythemia (ET, at 5.9%), and primary myelofibrosis (PMF, at 8.2%). In this study, more than 2 generations were involved in 60% of the pedigrees, while 60% had a single MPD phenotype with PV in the majority. In the largest report to date, involving 174 patients in 72 families, similar observations were made.