Worried about missing teeth or peculiar teeth in your child at an early age? Every smile tells a story - so do the symptoms of Ectodermal dysplasia. Often, the way teeth and jaws develop may give the first clue of ectodermal dysplasia, which can also affect hair, skin and sweat glands.

Introduction

“Ecto” is derived from a Greek word which means “an outer”, “dermal” pertains to skin and "dysplasia" refers to abnormal growth and development. Ectodermal dysplasia (ED) is a condition associated with abnormal development of the outer layer of embryonic tissues, which form skin, nails, hair, teeth and sweat glands. ED can also additionally manifest on other ectodermal tissues such as the mammary glands, Central Nervous System (CNS), inner and external ear, and ophthalmic (cornea, conjunctiva, lacrimal apparatus).¹

Typically, these abnormalities are caused by gene mutations. The most commonly occurring type of ectodermal dysplasia is hypohidrotic ectodermal dysplasia (HED), which is a condition transmitted as an X-linked recessive disorder.²

Dental abnormalities like hypodontia, i.e. congenitally missing teeth, abnormal tooth shape & texture, delayed eruption and jaw growth deformity can be early clues to decode the presence of ectodermal dysplasia in children, which can be further stepping stones in the diagnosis of probably a syndromic condition unknown to the clinician and the patient.

Classification of ED

There are over 100–200 types of ED, resulting in a wide distribution classification system. Freire-Maia in 1970 had given the first classification system, which was based on four main structures of the ectoderm that are affected, i.e. hair, teeth, nails, and sweat glands.²

Hypohidrotic ED is classified in Subgroup 1-2-3-4, which indicates all four classic ectodermal structures are affected. Advancements in genetic research have implemented a new classification according to genomic pattern, which was introduced in 2017 at the 8th International Conference on Ectodermal Dysplasia.² 

Dental manifestations in ectodermal dysplasia

Due to various forms of ED, there is widespread distribution of symptoms, and the clinical presentation of the disease can greatly depend on the patient type. Cleft palate/ lip, reduced saliva, thinner enamel and teeth prone to dental caries are commonly noticed oral symptoms. Typically noticed dental abnormality involves hypodontia, i.e. congenital absence of 1-6 teeth, microdontia, i.e. smaller than normal teeth, anodontia, i.e. complete absence of teeth, atypical tooth shape, malocclusion and delayed teeth eruption.

Dental manifestations of ectodermal dysplasia can be seen in various syndromic conditions such as Christ-Seimans Touraine syndrome, Haywell's syndrome, Goltz-Gorlin syndrome, Incontinentia Pigmenti, ED & immunodeficiency 1, odonto-onychodermal dysplasia, Schopf-Shulz-Passarge Syndrome, Acro-Dermato-Ungual-Lacrimal Tooth Syndrome(ADULT syndrome), Rapp-Hodgin Syndrome, Limb-Mammary Syndrome(LMS), arthrogryposis and ED, Dermo-odontodysplasia and Electrodactyly Ectodermal Dysplasia.^2,3

ED disorders and their associated dental abnormalities

• Hypohydrotic ectodermal dysplasia: It is an X- X-linked ectodermal dysplasia that predominantly affects males, though female carriers can show partial symptoms. It is basically a combination triad of hypohidrosis or anhidrosis, hypotrichosis and hypodontia. Typically, the features include sparse hair on the scalp and body with conical-shaped peg lateral incisors. Delayed eruption also leads to facial malformations, such as midfacial hypoplasia, which is characterised by a shortened midfacial aspect and thinning of the tooth-bearing areas of the jaw bones. The most common complication one should be aware of is hyperthermia because of decreased sweating, which can further lead to heat strokes in infants, causing death. In this condition, hair growth defects can be seen, i.e. sparse eyebrows and eyelashes. Dry skin, periorbital hyperpigmentation, i.e. around the eye socket, and darkness in skin tone can be appreciated. Mucosal gland abnormalities further lead to thick nasal secretion, which causes respiratory tract infections¹
• Incontinentia pigmenti: It is known as Bloch-Sulzberger syndrome. Most of these cases occur in females, as males fail to survive through pregnancy due to the lethal effects of gene mutation in them. Classical features include changes in skin condition in four different stages. Firstly, the baby is born with blisters or small red bumps or fluid-filled spots on the skin, which may look like a rash. Later, it progresses to wart-like like i.e. raised rough patches growing on skin that further turn darker in childhood and then paler in adolescence/ adulthood. Dental abnormalities noticed are delayed eruption, conical teeth, complete or partial absence of teeth, and cleft palate
• Onycho-odontodermal dysplasia: Severe oligodontia, i.e. missing six or more permanent teeth, is appreciated. Onchodysplasia refers to defective growth of cartilages, which affect bone growth, causing short stature or abnormally shaped bones, spine or joints and may cause dental or craniofacial abnormalities. Palmoplantar hyperkeratosis, which means the skin of the hands and feet becomes thick, rough, and sometimes hard or scaly, is also noticed along with dry skin, sparse hair and excessive sweating of palms and soles
• Schopf-Schulz-Passarge syndrome: In this condition, Palmoplantar Keratoderma, i.e. the skin of the hands and feet, becomes abnormally thick, hard, and sometimes cracked. Dental abnormalities include hypodontia, i.e. missing teeth. Sparse hair, nail shape deformity and multiple shiny, smooth, skin-colored to bluish bumps near the eyelid margin are also appreciated
• EEC syndrome: Ectrodactyly, ectodermal dysplasia and cleft lip/ palate syndrome has atypical features such as split hand/ foot deformity (ectrodactyly), thin, brittle nails,  light coloured, sparse hair, variable sweating and cleft lip/ palate. Furthermore, dental abnormalities appreciated are midfacial hypoplasia, i.e. reduced volume in the upper jaw³
• Ankyloblepharon ED Cleft lip/palate (AEC), Also known as Haywood's syndrome, also manifests in the oral cavity. Patients typically present with cleft lip or palate occurring in most cases, and Ankyloblepharon filiforme adnatum (fusion of the eyelids), which can be present near the canthus or corners of the eye or down the midline of the eye²
• Focal Dermal hypoplasia, or Goltz Gorlin syndrome, Clinical features consist of variety of craniofacial abnormalities including cleft lip, enamel hypoplasia and hypodontia and other enamel defects including microdontia (smaller teeth), gemination i.e. tooth tries to split into two during development, fusion i.e. when two separate tooth buds fuse together which further combined to form a single large tooth,  mulberry-like molars i.e. teeth that look small, rounded, and bumpy on the chewing surface., and alveolar notching i.e. small notches or irregularities in the bone margin around the teeth, instead of a smooth contour²
• Unlike others, there is also a condition named Non-syndromic tooth agenesis, which only affects teeth, i.e. congenitally missing teeth, caries-prone dentition and is not associated with other tissues of ectodermal origin, which is X X-linked gene mutation⁴

Diagnosis

The appearance of ectodermal dysplasia varies from patient to patient. Around 6-7^th week of embryonic development, Anodontia or any other dental changes take place. Certain craniofacial abnormalities, such as cleft lip/ palate, can be seen in a prenatal ultrasound. In the first year of life, it can be difficult to identify signs and symptoms. However, infants will have cycles of unexplained fever that lead to death due to hypohydrosis, which causes an inability to regulate body temperature. In early childhood, around 2 years, children start showing symptoms such as sparse hair, eczema, missing eyebrows or lashes, a face looking smaller due to depression of the nasal bridge, delayed and abnormal tooth eruptions and respiratory tract infections.

The diagnosis is based on multiple factors such as clinical signs and symptoms, microscopic examination of biopsy samples and genetic testing. In general, the most common features include sparse hair, excessive sweating and missing/ abnormal teeth. A relevant family history is also mandatory to rule out genetic predisposition and inheritance patterns. Prenatal genetic testing can be done via chorionic villus sampling or amniocentesis if positive findings are noticed in an ultrasound, such as missing tooth buds or limb anomalies.

Multidisciplinary management

The inclusion of a multidisciplinary team is crucial for the evaluation and management of ED. Once a definitive diagnosis is confirmed, educating the patient and their parents about the disorder, its complications, prognosis and management should be explained. Mostly in these cases, symptomatic treatments are the only options left to maintain the function and to lead a normal life for the patient. A holistic approach should be taken into consideration, which includes multidisciplinary involvement of dentists, paediatricians, orthodontists, Speech therapists, ENT specialists, geneticists, neurologists, physiotherapists, orthopaedic surgeons, dermatologists, and nutritionists. Psychiatric evaluation and family counselling should also be considered.

Dental management

Children with anodontia and oligodontia can be treated at an early stage with restorative and prosthetic rehabilitation. Early dental care is imperative for proper nutrition, speech development and socialisation. In pediatric patients, maintaining the primary dentition is important for proper jawbone and facial growth. Initially, in childhood, restorative treatment, i.e. conservative or root canal treatment of the affected teeth to be done. After proper follow-up of the previous treatment done to save the teeth, which were present, gives a favourable response, prosthetic rehabilitation with a transitional removable partial denture or a complete denture if no teeth are present, should be done with regular further follow-up to notice the jaw growth pattern.^2,4

Further, when the child reaches adolescence or adulthood, definitive treatment options such as implants can be placed with a success rate of 88.5-97.6 %.² This procedure can include adding bone volume in deficient areas for implant placement. Continuous follow-up should be done on a regular basis. The patient also has to be compliant to maintain oral hygiene to provide definitive treatment. If not able to do so, removable dentures are also an option to continue with.

General measures in the management of ectodermal dysplasia

• Apply regular moisturiser to affected dry areas
• Avoid damage to skin and hair by not overusing soaps and shampoos
• Regular application of sunscreen
• If feasible, an air-conditioned environment to be maintained
• Wearing a wet T-shirt, consuming excessive fluid
• Preferably swimming for regular sport activity
• Trimming nails regularly by filing with pumice stones
• Proper oral hygiene should be maintained. Fluoridated toothpaste can be used
• Saliva substitutes, humidification, saline nasal drops and artificial tears can be helpful in symptoms like dry mouth, dry eyes, etc
• Regular monitoring of the weight and height of patients must be done
• Adequate nutrition and supplements must be consumed

 Summary

Often, dental changes can be the primary clue to detect ectodermal dysplasia and its related conditions, which can hamper the overall health of the patient in future. Early dental intervention can invariably improve speaking,  eating and confidence of the child. Careful examination by respective specialists is very crucial to its management. Proper genetic counselling can further educate the patients and their families. New research in genetics and stem cells may bring better treatments in the future.