* The numbers are taken from the National Foundation for Ectodermal Dysplasias (NFED) database and are not based on medical literature. There are more than 180 distinct types of ectodermal dysplasias cited in the literature.
1. Ectodermal Dysplasia, Specific Type is Unknown by the NFED – 3,168 People
Almost half of the people on the NFED database reported having “ectodermal dysplasia” and didn’t report being diagnosed with a specific type. This is why the NFED has worked to develop a classification system for the ectodermal dysplasias which would help improve diagnosis. Without a specific diagnosis, affected individuals can still treat their symptoms. However, it’s important to know what specific type affects the individual for family planning purposes in order to stand the inheritance risks.
2. X-linked Hypohidrotic Ectodermal dysplasia (XLHED) – 1,763 people
Hypohidrotic ectodermal dysplasia (HED) is characterized by a reduced ability to sweat, missing teeth, and fine sparse hair. Individuals affected by HED share a similar facial appearance with thin, dark skin beneath the eye with extra folds or wrinkles, a depressed “saddle” nose, small narrow jaw, and small pointed teeth. Eruption of the teeth may be delayed, or only a few teeth may erupt. Additional features include dry eyes, eczema, asthma, ear wax impaction, dry nasal concretions, respiratory illness, sinusitis, or sparseness of saliva. HED may be inherited in one of three patterns: X-linked recessive, autosomal recessive and autosomal dominant.
3. Hypohidrotic Ectodermal Dysplasia (Patients didn’t know which of the 3 types they have. Typically, 95% of HED is XLHED.) – 900
See description for XLHED.
4. Ectrodactyly-Ectodermal Defects-Clefting (EEC) Syndrome – 336 people
EEC syndrome is a type of ectodermal dysplasia in which there is congenital absence of some of the fingers or toes, features of ectodermal dysplasia, and cleft lip or palate. While both hands and both feet are usually involved, exceptions have been noted. Abnormalities in the development of tear ducts can cause excessive tearing or a failure of the tear glands to develop may cause inflammation of the eyelids, cornea, and conjunctiva. Intolerance of light (photophobia) may occur. Skin and hair may be more lightly pigmented than normal, and a variety of hair problems may be experienced, from sparse hair to thick, unruly hair. The nails in some, but not all, people with the disorder may be abnormal. Various renal problems have been identified in individuals affected by EEC, but great variation in the type and severity exist. The most obvious abnormalities of the oral cavity include cleft palate with or without cleft lip. Congenital absence of teeth and pointed teeth are common. Conductive hearing loss (not nerve deafness) even without ear malformations has been noted in some individuals. EEC syndrome is inherited as an autosomal dominant disorder.
5. Clouston Syndrome– 194 people
Clouston syndrome is characterized by thick nails that grow slowly, sparse hair, thickness of the skin over the palms and soles, dark skin over the knees and elbows, white patches on the inside of the cheeks, thin eyebrows (outer portion only), and a reduced number of eyelashes. Individuals with this type have normal teeth and sweat normally. Intelligence is normal. Clouston syndrome is frequently called hidrotic ectodermal dysplasia because affected individuals sweat normally and exhibit no heat intolerance. Clouston syndrome is inherited as an autosomal dominant disorder.
6. Ankyloblepharon-Ectodermal Dysplasia-Clefting (AEC Syndrome) – 159 people
AEC syndrome, which includes the Rapp-Hodgkin syndrome, is characterized by ankyloblepharon (fused eyelids); sparse, wiry hair; skin erosions; unique pigmentary changes; nail changes; dental changes; subjective decrease in sweating capacity; and cleft lip/palate. Nearly 100% of affected babies have superficial skin erosions that range from very limited to severe, even life-threatening, full body involvement. Scalp erosions at birth and during infancy are typical and, when severe, can lead to scarring alopecia and hypotrichosis. Limb anomalies are also common. AEC syndrome is inherited as an autosomal dominant disorder.
7. Tooth and Nail Syndrome – 141 people
Individuals with the “tooth and nail” syndrome sweat and tolerate heat normally. Nails are spoon-shaped (concave), thin, and grow slowly. Many teeth are congenitally absent, but rarely are more than 20 permanent teeth missing. The teeth which are present may be peg-shaped or smaller than normal. Baby teeth may be retained until adulthood if they have no permanent successors. The density of scalp hair varies from normal to sparse, and the hair itself may be lightly pigmented. No other medical problems have been noted in patients affected by “tooth and nail” syndrome. Intelligence is normal. There are at least two types of “tooth and nail” syndrome: the Fried syndrome and the Witkop syndrome. The Fried syndrome is an autosomal recessive disorder, while the Witkop syndrome is an autosomal dominant disorder. Consequently, family history may be necessary to know the type a particular individual has.
8. Focal Dermal Hypoplasia (FDH) (also known as Goltz syndrome) – 94 people
Goltz syndrome has characteristic findings in the skin, ranging from small areas of absent skin to small areas of thin skin, especially on the scalp. The areas of defective skin may be abnormally pigmented, and fatty tissue may protrude through them. Frequently, affected individuals have lumps of raised tissue on the lips, gums, and base of tongue and around the mouth, anus, vulva, groin and arm pits. Affected individuals have absent, poorly developed, spoon-shaped, or grooved nails. While some affected individuals do not sweat normally over their entire bodies, their palms and soles may sweat excessively. Individuals with Goltz syndrome may have patches of hair loss on the scalp and pubis. Dental abnormalities may include irregular position of teeth, poor enamel, and malformed teeth. Other findings include asymmetry of the face, malformed ears, pointed chin, and wide-set eyes. Abnormal development of the eye, small eyes, and colobomas of the iris and the choroids, may occur. Frequently, fusion of fingers and toes and other abnormalities of the fingers or toes may be noted. Hearing loss has been reported, as have heart and kidney defects. Hernias and mental retardation are occasional features. It is usually, but not always, X-linked dominant (lethal in males). About 90% of affected individuals are female.
9. Incontinentia Pigmenti (IP) – 74 people
IP is a skin disorder characterized by blister-like lesions over the skin shortly after birth. There is great dispute in the medical world about whether or not IP is an ectodermal dysplasia. The lesions gradually change character, and marbled hyperpigmentation appears in early childhood. The areas of hyperpigmentation may fade during the second and third decades of life. By mid-life, affected adults have mild pigmentary changes only, including small areas of decreased pigmentation. People with IP may have missing or malformed teeth, patches of absent scalp hair, some learning disabilities, occasional seizures, and various problems with their eyes (the retinas) and their bones. Their nails also may be poorly formed. IP affects females almost exclusively (99%) and is caused by a gene carried on the X-chromosome that is lethal to males who inherit it.
10. Autosomoal Dominant Hypohidrotic Ectodermal Dysplasia (ADHED) – 58 people
See description for XLHED.
February is Ectodermal Dysplasias Awareness Month. NFED.org