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Hypohidrotic Ectodermal Dysplasia A Peer-Reviewed Publication Written by Sherri Lukes RDH, MS and Jennifer S. Sherry RDH, MSEd
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Publication date: November 2010Expiry date: October 2013
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Educational ObjectivesThe overall goal of this article is to provide the reader with in-formation on the signs and symptoms of ectodermal dysplasia and carrier status among patients. Upon completion of this course, the reader will be able to do the following:1. List the more common syndromes associated with
oligodontia2. List the various signs and symptoms of ectodermal
dysplasia3. List and describe the global incidence of female carriers for
AbstractMore than 120 syndromes are associated with oligodontia, including ectodermal dysplasia. The signs and symptoms of ec-todermal dysplasia include sparse hair; dry skin; few, malformed teeth; deficient sweat glands and dystrophic fingernails. Ecto-dermal dysplasia is most commonly the hypohidrotic X-linked version, affecting 80% of sufferers and the syndrome is carried by females. Knowing the signs and symptoms of ectodermal dysplasia may assist dentists and dental hygienists in identifying patients with the disease and possibly potential carriers.
IntroductionDental professionals commonly observe congenitally miss-ing teeth during the process of care. They should, however, be cognizant of various conditions and/or syndromes in which missing teeth and other dental abnormalities are manifestations. Hypodontia, which technically is defined as the absence of six teeth or less,1 is a common developmental anomaly in dentistry. Among the commonly missing teeth are third molars, maxillary lateral incisors and mandibular second premolars. Oligodontia, on the other hand, is defined as the absence of more than six teeth, excluding third molars, and is a less common finding.1,2 It is typically just one of a variety of signs manifested in several syndromes and can be one of the first signs that a person is af-fected by the syndrome.
There are over 120 syndromes in which oligodontia is one of the associated findings.2 The majority are hereditary. Those most commonly associated with missing teeth are ectodermal dysplasia (ED) and Down syndrome,3 and many of the remain-ing syndromes are very rare. When diagnosing oligodontia, the dental professional must look for additional manifestations of a syndrome, as there is an array of findings among the numerous syndromes. Some of the many syndromes in which oligodontia can be a finding include Seckel syndrome, Rieger syndrome, Wolf-Hirschhorn syndrome and Klippel-Feil syndrome.4,5,6,7
The ectodermal dysplasias represent a group of genetic disorders characterized by 150-170 clinical conditions.8,9 It can be the result of autosomal dominant, autosomal recessive or X-linked genetic expression and occurs in populations world-wide with an estimated incidence of one per 100,000 births.8-12 The most common form is the X-linked, hypohidrotic form, constituting 80% of those affected by the condition. The tissues
affected in their development are those derived from ectoderm and include skin, hair, nails, teeth and glands.8-19 Among the various sign and symptoms of hypohidrotic ectodermal dys-plasia (HED) are dry, hypoplastic skin; sparse scalp and body hair (alopecia or hypotrichosis); dystrophic fingernails; deficient sweat glands (hypohidrosis); oligodontia; and other dental de-fects. The few teeth that are present in HED patients tend to be malformed and smaller in size. Alveolar edentulous areas are often exemplified as hypoplastic, sharp and narrow ridges.15,20 These dental abnormalities are especially important in the early diagnosis of HED so appropriate treatment can be planned for the patient from childhood to adulthood.16,18
As with most diseases, there is great variability of signs and symptoms in those affected by HED. Since the syndrome is inherited as an X-linked recessive gene, it is only fully ex-pressed in males, which means all signs and symptoms are more numerous and severe in males than in females.13,16,21,22 The combined signs of HED result in a quite characteristic dento-craniofacial appearance for affected males (fig. 1), dis-tinguished by thin, fine hair; sunken eyes and nasal bridge (also called saddle nose); prominent forehead; and everted lips.20 Dental abnormalities include oligodontia or anodontia, coni-cally shaped anterior teeth, bud-shaped crowns, taurodontism, decreased mesio-distal diameter of molars and hypoplastic alveolar ridge.9,15,16,22
Figure 1. Affected male
With permission from NFED
Females are gene carriers for the disorder, which means the spectrum for signs and symptoms in females can range from unobservable to full expression of HED.10,15,20,21 Global studies report oligodontia, however, as one of the most common signs of carrier females, noting that 75% or more female carriers had abnormalities associated with their permanent teeth.14,15,22 Some researchers also note that carriers may go undiagnosed for HED if hypodontia is minor and no other signs and symptoms are noticed.2,15 Early prosthetic therapy is recommended for patients who present with the various forms of hypodontia.20
During the assessment phase of the dental hygiene process of care, it is possible that dental hygienists can aid in the diag-
nosis of female carrier states of HED through identification of dental abnormalities. The following case study is suspect for a carrier state of HED, undiagnosed as of yet by medical and dental professionals.
Medical HistoryPatient X is a 35-year-old Caucasian female who sched-uled a routine dental examination and prophylaxis ap-pointment in the clinic within a dental hygiene program at a Midwestern university. Her medical history was unremarkable, revealing no current diseases or pathologic conditions. She did have a history of taking the medications Advil and Zantac as well as a birth control pill. The patient used tobacco products for 15 years and continues to smoke about 10 cigarettes per day. She tried the smoking cessa-tion medication Chantix in the past but was unsuccessful at quitting. There is a family history of hypertension as well as diabetes.
Blood pressure was recorded as 130/90 (other vitals within normal limits)Weight: 230 pounds (reported by the patient)Height: 52 (reported by the patient)
Dental HistoryPatient X could not recall the date of her last dental ex-amination, prophylaxis or radiographs. She had a history of fever blisters on her lips but did not elaborate on specific information regarding this condition. The patient noted a history of clenching and grinding her teeth. When asked about one or both of her parents losing teeth in the past, she mentioned that her father (deceased) was congenitally missing several of his permanent teeth. She reported previ-ous orthodontic treatment. The patient stated she was not satisfied with the appearance of her teeth and would not be disturbed if she had to wear false teeth/dentures. Patient X worked in retail and did not have dental insurance.
Oral AssessmentIntra- and Extraoral ExaminationThe intra- and extraoral examination elicited a number of find-ings. The intra- and extraoral findings were as follows: Temporomandibular joint popping Small lesion on lower lip Slight hairy tongue Unable to classify occlusion due to missing teeth;
open bite was visible on the panoramic radiograph Multiple missing teeth (excluding third molars): #2, 4, 5, 6, 7, 10, 12, 15, 20, 21, 22, 23, 28, 29 and 31 Retained deciduous teeth A, L, and T with no successor Amalgam restorations: #3-O, #14-O, #18-O, #30-O and T-O
Gingival/periodontal status: localized areas of gingivitis, moderate supra- and subgingival calculus noted on the entire dentition
4 mm. pockets on #3-ML, #13-DL and #30-MB T: recession of 4 mm on the buccal surface A: recession of 3 mm on the buccal surface Periodontal diagnosis: localized chronic periodontitis
with slight (< 2 mm) clinical attachment loss (CAL) Oral hygiene: plaque-free score 86.6%
Figure 2. Panoramic radiograph
Radiographic assessmentThe radiographic findings were as follows:Panoramic radiograph (fig. 2): Mandibularrightmidlinedeviation(fig.3) Apicalrootresorption:#8,9severeresorptionA,T,
and L(no mobility noted) 45degreerotation:#13 Abnormalmorphology:#18macrodontia Boneloss:localizedareasofhorizontalandverticalbone
alveolar ridge Prematurewearonsuperioraspectofrightcondyle Periapical radiographs (figs. 4-6): Conicalrootstructure:#3,A Severerootresorption/bonelossonTappearstohave
little to no supporting bone, Patient X later stated T is sensitive to pressure
Abnormalmorphology:#18increasedmesial/distalwidth of crown with abnormally wide pulp chamber
Figure 3. Midline deviation
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Figure 4. Periapical radiograph
Figure 5. Periapical radiograph
Figure 6. Periapical radiograph
Additional Assessment ResultsAfter the oral and radiographic assessment, supervising fac-ulty at the dental hygiene clinic suspected a syndrome such as hypohidrotic ectodermal dy