Most notable is the case of ABT-737 and its orally active analogue, ABT-263 (Navitoclax), both of which inhibit BCL-2, BCL-XL and BCL-w, whereas a related analogue, ABT-199 selectively inhibits BCL-2, and not BCL-XL, thus circumventing a dose-limiting thrombocytopenia, associated with BCL-XLinhibition [4-10]. The gene discussed is BCL2L1; the disease is Thrombocytopenia.