KCNN4 and sickle cell disease: KCa3.1 knockout mice are viable and of normal appearance, produce normal litter sizes, and exhibit rather mild phenotypes.36-38 High doses of TRAM-34 administered to mice over many weeks are well tolerated,39 and the orally available KCa3.1 blocker ICA-17043 has been administered to human subjects in phase 2 and 3 trials of sickle cell disease with minor side effects.40