PBXIP1 and cardiomyopathy: The fact that Pbxip1 and other genes are differentially regulated in sex-specific transcription patterns in Prdm16csp1/wt hearts partially explains the sex-specific phenotype that we observed.20 The recent identification of Prdm14 as a determinant of sex-biased expression patterns in early heart development further highlights the critical impact of the Prdm gene family as determinants of cardiac function.53 Our findings suggest a sexual dimorphism for PRDM16 associated cardiomyopathy, with a more penetrant phenotype that likely occurs earlier in females.