FAM20A and amelogenesis imperfecta type 1G: With the breakthrough discovery that FAM20A mutations cause AI associated with a variety of oral manifestations including eruption failures and gingival enlargement [24], we performed mutation analyses in three families exhibiting this pattern of defects, and in each case we identified disease-causing mutations in both FAM20A alleles and made the diagnosis of Amelogenesis Imperfecta and Gingival Fibromatosis Syndrome” (AIGFS).