In heart failure, reduced mouse Rbfox2 expression inhibits the inclusion of exon 13 in Enah and exon 4 in Sorbs2, while during heart development,38 mouse Rbfox2 governs the balance by repressing Tpm1 isoforms containing exon 6a40 and promoting Tpm1 isoforms with exon 9b.10 The gene discussed is TPM1; the disease is heart failure.