Enamel renal syndrome with associated amelogenesis imperfecta, nephrolithiasis, and hypocitraturia: A case report

Enamel Renal Syndrome: A Systematic Review

The enamel renal syndrome (ERS) is a rare autosomal recessive disease that is associated with mutations in the FAM20A gene. The syndrome is characterized by impaired amelogenesis of the hypoplastic type and nephrocalcinosis, presenting with presence of thin or absence of enamel, late dental eruption, intrapulpal calcifications, bilateral nephrocalcinosis, and normal plasma calcium level. The objective is to characterize ERS by systematically literature reviewing, highlighting the main findings of the syndrome to increase knowledge about this condition in the health professionals. The study is a systematic review of the scientific literature, whose research was developed in the PubMed database in March 2018. A total of 69 articles were found. Two authors analyzed their abstracts and selected, according to the language and main subject, 30 articles to write this study. A total of 69 patients were cited in the studies and their data were analysed. There was gender equivalence and the ages ranged from 1 to 64 years old. There is a clear hereditary relation of the syndrome, since there was consanguinity in 18 cases, indicating a percentage of 26.08% and family history in 30 cases (43.47%). Laboratory changes vary greatly from patient to patient and may even remain unchanged. The relationship between the syndrome and the mutation in the FAM20A gene can be proven from the data, since all patients with ERS screened by the mutation were positive. With the advancement of the ERS studies, some associations with the syndrome are suspected, such as the presence of gingival fibromatosis, hearing loss, and hypertrichosis. Thus, it is noticed that the syndrome does not show a predilection for gender or age and there is a strong hereditary character, marked by the consanguinity and family history of the patients. The association with the FAM20A gene is reinforced, since the mutation was identified in all patients analyzed.

Two new families with enamel renal syndrome: A novel FAM20A gene mutation and review of literature

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.

Syndromes with gingival fibromatosis: A systematic review

OBJECTIVE

The aim of systematic review was to describe the phenotypes and molecular profiles of syndromes with gingival fibromatosis (GF).

METHODS

A comprehensive search of PubMed, LILACS, Livivo, Scopus, and Web of Science was conducted using key terms relevant to the research questions and supplemented by a gray literature search. The Methodological Quality and Synthesis of Case Series and Case Reports in association with the Case Series and Prevalence Studies from the Joanna Briggs Institute critical appraisal tools were used for the risk of bias. We followed the PRISMA checklist guidelines.

RESULTS

Eighty-four studies reporting GF as an oral manifestation of a syndrome were identified in this review. Enamel renal syndrome was the most frequently reported syndrome with GF, represented by 54 individuals in 19 studies, followed by Zimmermann-Laband syndrome with 24 individuals in 15 studies and Costello syndrome, which was presented in a case series study with 41 individuals. Among reported cases, other clinical manifestations such as hypertrichosis, ectopic gingival calcification, and cherubism were described.

CONCLUSIONS

The results emphasize the need of systematic oro-dental-facial phenotyping for future descriptions as well as further molecular analysis in order to better understand the occurrence of syndromic GF.

FAM20A Gene Mutation: Amelogenesis or Ectopic Mineralization?

Background and objective:FAM20A gene mutations result in enamel renal syndrome (ERS) associated with amelogenesis imperfecta (AI), nephrocalcinosis, gingival fibromatosis, and impaired tooth eruption. FAM20A would control the phosphorylation of enamel peptides and thus enamel mineralization. Here, we characterized the structure and chemical composition of unerupted tooth enamel from ERS patients and healthy subjects.

Methods: Tooth sections were analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), and X-Ray Fluorescence (XRF).

Results: SEM revealed that prisms were restricted to the inner-most enamel zones. The bulk of the mineralized matter covering the crown was formed by layers with varying electron-densities organized into lamellae and micronodules. Tissue porosity progressively increased at the periphery, ending with loose and unfused nanonodules also observed in the adjoining soft tissues. Thus, the enamel layer covering the dentin in all ERS patients (except a limited layer of enamel at the dentino-enamel junction) displayed an ultrastructural globular pattern similar to one observed in ectopic mineralization of soft tissue, notably in the gingiva of Fam20a knockout mice. XRD analysis confirmed the existence of alterations in crystallinity and composition (vs. sound enamel). XRF identified lower levels of calcium and phosphorus in ERS enamel. Finally, EDS confirmed the reduced amount of calcium in ERS enamel, which appeared similar to dentin.

Conclusion: This study suggests that, after an initial normal start to amelogenesis, the bulk of the tissue covering coronal dentin would be formed by different mechanisms based on nano- to micro-nodule aggregation. This evocated ectopic mineralization process is known to intervene in several soft tissues in FAM20A gene mutant.