RFX4 and Hydrocephalus: We first identified the transcript encoding what is now known as RFX4 isoform 1 in mice expressing a transgene encoding a cardiac-specific cytochrome P450 epoxygenase that developed hydrocephalus; we demonstrated that the transgene had disrupted the Rfx4 gene, leading to the absence of RFX4 isoform 1 expression [10].