For example, the small molecule ABT-263 inhibits both Bcl-2 and Bcl-xL, but Bcl-xL cross-reactivity leads to dose-limiting thrombocytopenia (Rudin et al., 2012; Roberts et al., 2012; Schoenwaelder et al., 2011). Here, BCL2L1 is linked to Thrombocytopenia.