BCL2 and polycystic kidney disease: Additionally, we assessed platelet and megakaryocyte counts in young (1–5-week old) mice with a constitutive deletion of Bcl2. 24 Despite their various phenotypic abnormalities, including kidney polycystic disease, growth retardation and lymphopaenia, blood platelet counts (Figure 1f) and bone marrow and spleen megakaryocyte numbers (Figure 1g) in Bcl2−/− mice were comparable with those of wild-type controls.