EDA Mutations Causing X-Linked Recessive Oligodontia with Variable Expression.

BACKGROUND/

OBJECTIVES

The ectodysplasin A (EDA) gene, a member of the tumor necrosis factor ligand superfamily, is involved in the early epithelial-mesenchymal interaction that regulates ectoderm-derived appendage formation. Numerous studies have shown that mutations in the EDA gene can cause X-linked ectodermal dysplasia (ED) and non-syndromic oligodontia (NSO). Accordingly, this study aimed to identify the causative genetic mutations of the EDA gene.

METHODS

We investigated EDA gene mutations in two X-linked oligodontia families using candidate gene sequencing and whole-exome sequencing, with a single proband identified and studied for each family. The first family included a patient with NSO, while the second family had a patient exhibiting variable expression of ED.

RESULTS

Mutational analysis identified two missense mutations in the EDA gene (NM_001399.5): one novel mutation, c.787A>C p.(Lys263Gln), in family 2; and one previously reported mutation, c.457C>T p.(Arg153Cys), in family 1. All mutated residues are evolutionarily highly conserved amino acids. The p.(Arg153Cys) mutation would destroy the furin recognition site and affect the cleavage of EDA. The p.(Lys263Gln) mutation in a TNF homology domain would interfere with the binding of the EDA receptor. The p.(Lys263Gln) mutation was associated with NSO, while the other mutation demonstrated ED.

CONCLUSIONS

This study helps to better understand the nature of EDA-related ED and NSO and their pathogenesis, and it expands the mutational spectrum of EDA mutations.