Msx2 Deficiency in Mice Causes Pleiotropic Defects in Bone Growth and Ectodermal Organ Formation

Msx2-deficient mice exhibited multiple developmental defects, including impaired skull ossification, persistent calvarial foramen, and issues in endochondral bone formation due to reduced proliferation of osteoprogenitors. These defects mirrored human MSX2 haploinsufficiency in parietal foramina. Additionally, Msx2-mutant mice showed abnormalities in tooth, hair follicle, and mammary gland development, as well as seizures linked to cerebellar development issues. The severity of these phenotypes increased with the combined loss of Msx1, underscoring the importance of Msx gene dosage in organogenesis.