Consistent with the increased necrotic core sizes seen in plaques from Ldlr KO mice lacking S1PR1 in BM-derived myeloid cells, these mice also exhibited higher levels of cellular apoptosis within atherosclerotic plaques than Ldlr KO mice with intact myeloid S1PR1 after HF diet-feeding for nine weeks. The gene discussed is S1PR1; the disease is hydrops fetalis.