SFRP4 and skeletal dysplasia: Importantly, skeletal phenotypes were described for Fam20c (non-lethal Raine syndrome), Lrrk1 (osteosclerotic metaphyseal dysplasia), Pappa2 (short stature), Sfrp4 (Pyle's disease), and Slc10a7 (skeletal dysplasia) prior to knowledge of the human skeletal dysplasias when mutated in humans (84).