LEPROTL1 and hypertrophic cardiomyopathy: The known contribution of Fzd8 to canonical β-catenin signaling and the WNT pathway15 is a likely mechanism to explore and potentially assign to the variant Fzd8. By contrast, the hypertrophic cardiomyopathy that we identified in Leprotl1-mutant mice suggests functions of this gene in addition to its known role in growth (that is, GH in the liver) and metabolism16.