Anti-ENAM monoclonal antibody, clone 3D23

Amelogenesis imperfecta (AI) is an inherited disorder that is associated with mutations in five genes (AMEL; ENAM; MMP20; KLK4 and FAM83H) with a wide range of clinical presentations (phenotypes). It affects the structure and appearance of enamel of all teeth, both in the primary and secondary dentition. In this review paper, we look at the epidemiology, classification, aetiology, clinical description and diagnosis of AI. In the following three papers of this series, we aim to describe the role of paediatric dentists, orthodontists and restorative dentists in the clinical management of patients with AI.

Amelogenesis imperfecta is a group of inherited diseases affecting the quality and quantity of dental enamel. To date, mutations in more than ten genes have been associated with non-syndromic amelogenesis imperfecta (AI). Among these, ENAM and LAMB3 mutations are known to be parts of the etiology of hypoplastic AI in human cases. When both alleles of LAMB3 are defective, it could cause junctional epidermolysis bullosa (JEB), while with only one mutant allele in the C-terminus of LAMB3, it could result in severe hypoplastic AI without skin fragility. We enrolled three Chinese families with hypoplastic autosomal-dominant AI. Despite the diagnosis falling into the same type, the characteristics of their enamel hypoplasia were different. Screening of ENAM and LAMB3 genes was performed by direct sequencing of genomic DNA from blood samples. Disease-causing mutations were identified and perfectly segregated with the enamel defects in three families: a 19-bp insertion mutation in the exon 7 of ENAM (c.406_407insTCAAAAAAGCCGACCACAA, p.K136Ifs*16) in Family 1, a singlebase deletion mutation in the exon 5 of ENAM (c.139delA, p.M47Cfs*11) in Family 2, and a LAMB3 nonsense mutation in the last exon (c.3466C>T, p.Q1156X) in Family 3. Our results suggest that heterozygous mutations in ENAM and LAMB3 genes can cause hypoplastic AI with markedly different phenotypes in Chinese patients. And these findings extend the mutation spectrum of both genes and can be used for mutation screening of AI in the Chinese population.