KL and Cognitive impairment: Mice deficient in Klotho exhibit a phosphate imbalance and hyperphosphatemia due to impaired urinary phosphate excretion, but significantly develop a complex progeric phenotype including poor growth, atrophy of multiple organs, vascular calcification (VC), sarcopenia, cardiac hypertrophy and fibrosis, cognitive impairment, and shortened lifespan (1, 2, 5).