Candidate gene strategy reveals ENAM mutations

Amelogenesis imperfecta (AI) is a genetically and phenotypically heterogeneous genetic disorder affecting tooth enamel without other non-oral syndromic conditions. Based on a review of the literature, the authors constructed a candidate-gene-based mutational analysis strategy. To test the strategy, they identified two Turkish families with hypoplastic enamel without any other non-oral syndromic phenotype. The authors analyzed all exons and exon/intron boundaries of the enamelin (ENAM) gene for family 1 and the DLX3 and ENAM genes for family 2, to identify the underlying genetic etiology. The analysis revealed 2 ENAM mutations (autosomal-dominant g.14917delT and autosomal-recessive g.13185-13186insAG mutations). A single T deletion in exon 10 is a novel deletional mutation (g.14917delT, c.2991delT), which is predicted to result in a frameshift with a premature termination codon (p.L998fsX1062). This result supports the use of a candidate-gene-based strategy to study the genetic basis for AI.