Enamel renal syndrome (ERS) or so-called amelogenesis imperfecta type IG is a very rare disorder characterized by the triad of amelogenesis imperfecta, gingival enlargement and nephrocalcinosis. It is caused by biallelic mutations in the FAM20A gene. Herein, we report two unrelated patients with ERS. Our patients presented with the characteristic features of the syndrome, and amelogenesis imperfecta and gingival hyperplasia were the main complaint. Strikingly, they both had long face, thick lips, notched upper central incisors, and thick alveolar ridge which have never been reported before in patients with ERS. Gingival biopsy showed psammomatous calcifications, and renal ultrasound revealed bilateral nephrocalcinosis in the two patients. Mutational analysis of the FAM20A gene identified two homozygous mutations including a novel one (c.915_918delCTTT, p.Phe305Leufs*76 and c.1219 + 3_1219+6delAGGT). Our data expand the phenotypic and mutational spectrum of FAM20A gene and reinforce the importance of kidney examination and follow up for all patients with amelogenesis imperfecta unless FAM20A mutations were ruled out.

牙釉质肾综合征（ERS）或所谓的牙釉质不全症IG型是一种非常罕见的疾病，其特征是牙釉质不全，牙龈增大和肾钙化三联征。它是由FAM20A基因中的双等位基因突变引起的。在此，我们报告了两名与ERS无关的患者。我们的患者表现出该综合征的特征，主要表现为釉质生成不全和牙龈增生。令人惊讶的是，它们都长着脸，嘴唇浓密，上中切牙有缺口，而牙槽较厚，这在ERS患者中从未见过。两名患者的牙龈活检显示为鳞状钙化，肾超声显示为双侧肾钙化。FAM20A的突变分析该基因鉴定了两个纯合突变，包括一个新的突变（c.915_918delCTTT，p.Phe305Leufs * 76和c.1219 + 3_1219 + 6delAGGT）。我们的数据扩大了FAM20A基因的表型和突变谱，并加强了肾脏检查的重要性，并对所有患有牙釉质发育不全的患者进行了随访，除非排除了FAM20A突变。