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. Here, FRAS1 is linked to congenital diaphragmatic hernia.