FREM1 and congenital diaphragmatic hernia: After identification of a FRAS1-related extracellular matrix 1 (FREM1) deletion in a child with isolated left-sided posterolateral CDH that was covered by a membranous sac, Beck et al. [48] created a Frem1-deficient mouse model that exhibits a similar phenotype including a retrosternal diaphragmatic defect and decreased levels of cell proliferation in the anterior portion of the developing diaphragm, demonstrating that FREM1 deficiency can cause CDH in both humans and mice.