Elevated FGF-23 levels contribute to decreased 1,25-dihydroxy vitamin D3 levels [162], secondary hyperparathyroidism [163], suppression of osteoblast differentiation, and matrix mineralization in vitro and in vivo [122] and are associated with vascular calcification [157, 164], endothelial dysfunction [165, 166], cardiovascular disease [167], mortality [163, 167, 168], HF, and nonvertebral fractures in elderly men [169]. The gene discussed is FGF23; the disease is hydrops fetalis.