Loss of epithelial FAM20A in mice causes amelogenesis imperfecta, tooth eruption delay and gingival overgrowth

Loss of the Fam20A gene causes defects in tooth enamel, excessive growth of the gums, and delayed tooth eruption in mice. Mutations in FAM20A have been linked to many of these same dental problems in humans, but the molecular link between the gene and disease was unknown. A team led by Chun-Lin Qin of Texas A&M University Baylor College of Dentistry in Dallas, USA, and Li Chen of the First Affiliated Hospital of Harbin Medical University China generated mouse models to track the expression of Fam20A in dental development and to test the effects of inactivating the gene. They found that cells that deposit tooth enamel began to express the gene in the mandibular first molars within a day of birth and that loss of Fam20A causes dental abnormalities consistent with those seen in humans.