UNCOMMON FORM OF ECTODERMAL DYSPLASIA: TRICHO-DENTO-OSSEOUS SYNDROME

Abstract

<h3>Background</h3> Tricho-dento-osseous syndrome (TDOS) is an autosomal dominant genetic disorder, which is characterized by inherited defects in tissues that arise from epithelial–mesenchymal interaction. The minimal diagnostic criteria for TDOS include enamel hypoplasia, posterior taurodonts, autosomal dominant inheritance pattern, tightly curly hair at birth, and/or radiographic evidence of bone sclerosis. Some authors have questioned whether amelogenesis imperfecta of the hypomaturation–hypoplasia type with taurodontism (AIHHT) and TDOS are distinct conditions or denote a spectrum of the same disease. <h3>Objective(s)</h3> The aim of this study was to increase awareness of TDOS. <h3>Results</h3> A 25-year-old female patient was seeking restorative treatment for the yellowish-brown discoloration of her teeth. Clinical evaluation revealed that she had multiple missing teeth, discolored teeth, frontal bossing, and a concave profile. She was otherwise healthy and not taking any medications. Her medical history indicated a previous diagnosis of ectodermal dysplasia (ED). Panoramic radiography and cone beam computed tomography (CBCT) revealed multiple missing and impacted teeth, as well as retained primary teeth. Reduction in enamel thickness on deciduous and permanent teeth was observed, in addition to taurodont appearance of second permanent molars. Generalized homogeneous ground-glass trabecular pattern in the maxilla and the mandible with a square shape of mandible was noted. <h3>Discussion/Conclusions</h3> In this report, we describe an unusual phenotype of ED, which represents a group of inherited conditions in which 2 or more ectodermally derived anatomic structures fail to develop. TDOS is an uncommon form of ED. The dental findings are clinically similar between TDOS and AIHHT; however, patients with AIHHT lack changes in their hair and bone. In cases where hair, bone, and nail changes are not significant, genetic analysis may help in differential diagnosis. TDOS is genetically linked to markers on chromosome 17 q21.