In summary FGF23 is likely a causal factor in production of HFpEF because it fulfills criteria for causality (Rabkin and Sackett, 1982[90]) being able to predict the development of the condition, correlates with the severity of the condition and has a reasonable biologic mechanism, specifically FGF23 can stimulate cardiac hypertrophy and/or cardiac fibrosis which will produce diastolic dysfunction. The gene discussed is FGF23; the disease is cardiac hypertrophy.