Working toward delivering a significantimprovement in the health and quality of lifeto future generations living with XLHED
Information for Professionals – Information for Dentists
Written by Tim Wright, DDS MS - University of North Carolina School of Dentistry
The ectodermal dysplasias (ED) are a diverse group of inherited disorders characterized by developmental abnormalities of two or more of the following tissues: hair, teeth, nails, sweat glands and other ectodermal derived structures (such as salivary glands, mammary glands, limbs). EDs are caused by mutations in genes that are critical for normal development of these tissues with the most common being the X-linked form of ED associated with mutations in the ectodysplasin gene (EDA). The oral manifestations of the ectodermal dysplasias are as diverse as the genetic causes of these conditions.
Hypohidrotic ED (deficiency in sweating as part of the disorder) is the most common form of ectodermal dysplasia and is associated with numerous oral health issues with missing a majority teeth being a predominant feature.
Tooth formation begins from the oral epithelium that is an ectodermal tissue. The failure of teeth to develop or erupt (hypodontia) and sharp pointed front teeth are common features of many EDs. Missing or pointed malformed front teeth can be the first presenting features of ED in infants or toddlers. While missing teeth or delayed tooth eruption have a variety of causes, the lack of tooth eruption after 12 months of age in an infant could be an indication of ED and should be evaluated by a dentist. Depending on the type of ED there can be enamel defects, changes in the shape, position and number of teeth, and abnormalities in the timing of tooth eruption. Having enamel defects increases the risk of developing tooth decay and should be evaluated by dentist.
Because many oral structures are derived from ectodermal tissues, other manifestations of ED such as cleft lip with or without cleft palate can occur. Orofacial clefting is a common feature of ED conditions caused by mutations in the p63 gene. The salivary glands are derived from ectoderm and thus can develop abnormally in ED leading to deficient salivary flow or dry mouth. Deceased salivary flow increases the risk of developing tooth decay and is thus important to diagnose so appropriate preventative therapies can be implemented. Due to the diverse and complex nature of oral manifestations associated with the different EDs, early prevention and planning for future treatment is indicated.