More interestingly, the Framingham Heart Study investigators have recently shown that moderately elevated serum ALT or AST levels (>40 U/L for either marker) were independently associated with an increased incidence of AF over a 8-year follow-up period in a community-based cohort of 3,744 adults, who were free of clinical heart failure at baseline [16]. The gene discussed is GPT; the disease is atrial fibrillation.