However, the accurate measurement of platelet size in IT subjects presents notable difficulties because some of the less rare forms, such as MYH9-related disease (MYH9-RD), monoallelic Bernard-Soulier syndrome (BSS) and biallelic BSS, may present platelets that, due to their very large size, are not recognized by the electronic counters, which therefore underestimates not only the platelet count but also the mean platelet volume (MPV) (Balduini et al, 2011; Savoia et al, 2011; Noris et al, 2012). The gene discussed is MYH9; the disease is Bernard-Soulier syndrome.