The association between FAM20A and a syndrome that included severe enamel hypoplasia and gingival hypertrophy was confirmed by mutational analyses in four additional families that identified three homozygous FAM20A mutations (c.34_35delCT; c.813-2A>G; c.1175_1179delGGCTC) and compound heterozygous mutations (c.590-2A>G with c.826C>T) in four families [25]. This evidence concerns the gene FAM20A and dental enamel hypoplasia.