While efflux of labeled cholesterol can be modified by SRB1 expression in vitro, knocking down SRB1 in vivo (in mice) not only does not decrease HDL-C (as would have been expected if SRB1 efflux were contributing to plasma HDL-C levels), but dramatically increases HDL-C and atherosclerosis [37]. The gene discussed is SCARB1; the disease is atherosclerosis.