FREM1 and renal agenesis: To determine if Frem1 and Slit3 interact genetically in the development of CDH, renal agenesis and/or lung lobulation defects, we crossed Frem1eyes2/eyes2 mice to mice in which one copy of the Slit3 gene has been disrupted by insertion of a Sleeping Beauty-tyrosinase transposon (Slit3+/−) [46].