|Year : 2016 | Volume
| Issue : 1 | Page : 55-57
Yogita Khalekar1, Amit Zope2, Lalit Chaudhari1, Ujawala Brahmankar1
1 Department of Oral Medicine and Radiology, ACPM Dental College, Dhule, Maharashtra, India
2 Department of Orthodontics and Dentofacial Orthopedics, ACPM Dental College, Dhule, Maharashtra, India
|Date of Web Publication||11-Aug-2016|
Department of Oral Medicine and Radiology, ACPM Dental College, Dhule, Maharashtra
Source of Support: None, Conflict of Interest: None
Ectodermal dysplasias (EDs) are a heterogeneous group of disorders characterized by developmental dystrophies of ectodermal structures that may result in hypotrichosis, or hypodontia and hypohidrosis. The X-linked recessive ED (Christ-Siemens-Touraine syndrome) is the most common disorder; it affects males and is inherited through female carriers. Most patients with EDA have a normal life expectancy and normal intelligence. However, the lack of sweat glands may lead to hyperthermia, followed by brain damage or death in early infancy, if unrecognized. Thus, an early diagnosis is important. For the patients and the dentists tooth agenesis and its secondary effects on growth and development of the jaws is the most significant clinical and therapeutically problem.
Keywords: Christ-Siemens-Touraine syndrome; ectodermal dysplasia; hypodontia; hypohidrosis; hypotrichosis; tooth agenesis
|How to cite this article:|
Khalekar Y, Zope A, Chaudhari L, Brahmankar U. Ectodermal dysplasia. Indian J Multidiscip Dent 2016;6:55-7
| Introduction|| |
Ectodermal dysplasias (EDs) are a heterogeneous group of disorders characterized by developmental dystrophies of more than one ectodermal structure. These disorders are congenital, diffuse, and nonprogressive.  The prevalence of the disorder is approximately 1 in 100,000 live birth.  More than one hundred and seventy different varieties of this clinical conditions have been recognized.  Freire-Maia and Pinheiro proposed the first classification system of the EDs in 1982 with additional updates in 1994 and 2001. Their original classification system stratified the EDs into ten different subgroups according to the presence or absence of (a) hair anomalies or trichodysplasias, (b) dental abnormalities, (c) nail abnormalities or onychodysplasias, and (d) eccrine gland dysfunction or dyshidrosis.
From the clinical point of view, two main forms have been distinguished: (A) hypohidrotic form/Christ-Siemens-Tourian syndrome which exhibits the classic triad-hypohidrosis, hypotrichosis, and hypodontia. (B) Hidrotic form/Clouston syndrome exhibits hair, nail defect, and spare sweat glands abnormality.
Here, we report a case of ED in a 6-year-old male patient.
| Case Report|| |
A 6-year-old male student born of nonconsanguineous marriage presented with congenital absence of teeth. Clinical examination of the patient showed very fine and brittle hair on the scalp, large and oblique set ears, as well as complete absence of eyebrows and even eyelashes. Frontal bossing, slightly saddled nose, and full and everted lips were also noted [Figure 1] and [Figure 2]. Dental examination revealed a complete absence of mandibular teeth and partial anodontia in the maxillary arch. The maxillary anteriors (13 and 23) were conical in shape [Figure 3]. Dental history revealed delayed eruption and partial anodontia in primary dentition as well. The patient also gave a clinical history of almost complete absence of sweating from birth.
Orthopantomograph revealed completely edentulous mandibular arch and partial edentulous maxillary arch with the presence of only two conical-shaped teeth in the anterior region. Both the alveolar ridges were underdeveloped [Figure 4]. The combined clinical and radiographic findings pointed toward a diagnosis of hypohidrotic ED. No positive family history was found. He is the second child and the only affected member in the family. He is having normal palatal arch, normal oral mucosa, and his nails are unaffected.
|Figure 4: Orthopantomograph showing hypodontia and underdeveloped alveolar ridges|
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| Discussion|| |
The EDs are congenital, diffuse, and nonprogressive disorders. It is inherited as a cross-linked recessive trait so that the frequency and severity of the condition are more pronounced in males than in females. It was redefined by Freire-Maia as a developmental defect which at embryonic level affects the ectoderm and therefore the tissues and structures derived from it. Thus, it affects the development of keratinocytes and causes aberrations in the hair, sebaceous glands, eccrine and apocrine glands, nails, teeth, lenses and conjunctiva of the eyes, anterior pituitary gland, nipples, and the ears.  From the clinical point of view, two main forms have been distinguished:
The hypohidrotic form exhibits the classic triad-hypohidrosis, hypotrichosis, and hypodontia. Usually, X-linked recessive inheritance is seen. Males are affected severely, while females show only minor defects. In the hidrotic form teeth, hair and nails are affected. The sweat glands are usually spared. It is usually inherited as an autosomal dominant trait.
- Hypohidrotic form/Christ-Seimens-Tourian syndrome
- Hidrotic form/Clouston syndrome.
[Table 1] shows differences between the hidrotic and hypohidrotic forms of ED.  In the hypohidrotic form, the skin is soft thin, and dry. Partial or complete absence of sweat glands is responsible for the inability to perspire and accounts for intolerance to heat and frequent hyperthermia. Palms and soles are hyperkeratotic; pseudorhagades are present around the eyes. Atopic eczema is common, especially in flexures during early childhood. In a newborn, a "plastic wrap" appearance of the skin is characteristic of hypohidrotic type. In the hidrotic type, sweat glands develop partially; ducts may be formed but secretory coils are absent and there are reduced number of sweat pores. Scalp hair is often fine, stiff, and short. Eyelashes and eyebrows are scanty and often missing. 
|Table 1: Differences between the hidrotic and hypohidrotic forms of ectodermal dysplasia |
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Genetic studies of more than three hundred cases have revealed the X-linked mode of inheritance with its gene locus being Xq11-21.1, the gene is carried by the female but manifested in the male. However, there are reports of multiple siblings being affected and of females suffering with this condition.  Mutations in EDA, EDAR, and EDARADD genes are now identified to cause hypohidrotic ED. These genes provide instructions for making proteins that work together during embryonic development. These proteins form part of a signaling pathway that is critical for the interaction between the two germ layers the ectoderm and mesoderm. In the early embryo, these cell layers form the basis for many of the body's organs and tissues. Ectoderm-mesoderm interaction is essential for the formation of several structures that arise from the ectoderm including skin, hair, nails, teeth, and sweat glands. Mutation in the EDA, EDAR, or EDARADD gene prevents the normal interaction between ectoderm and mesoderm and impairs the normal development of hair, sweat glands, and teeth. The improper formation of these ectodermal structures leads to the characteristic features of hypohidrotic ED. ,
The presentation of thin eyebrows and partial anodontia observed in our case is in agreement with existing literature.  Whereas, the observation of normal form and shape of finger and toenails in the present case are in accordance with the previous observation of Shaw. The patient was the only child of his parents exhibiting features of ED. No similar case of ED has been identified among the relatives, which suggests that the propositus was probably a fresh mutation or due to translocation of genes as was suggested in a few other literature. 
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]