Ectodermal Dysplasia is a rare group of inherited disorders.
The disorders arise from disturbances in one or more ectodermal structures
and their accessory appendages. The absence of, or deficient function of, at
least two derivatives of the ectoderm constitutes a form of ED. Each
combination of defects represents another type of ED and has a specific
name. At least 150 different forms of Ed have been identified.
Individuals affected by ED have at least two or more of
the following manifestations:
1.Absent or malfunctioning sweat glands. The patient may
suffer from dry skin, yperthermia, and unexplained high fever as a result of
the deficiency of sweat glands. 2.Dental anomalies include missing or
underdeveloped teeth
3.Varying degrees of Alopecia resulting from defective hair follicles.
4.Malformed or missing fingers and toes. 5.Malformed fingernails and
toenails, to varying degrees.
In addition, patients may have poorly functioning mucous
membranes, cleft lip and palate, deficient saliva, hearing or visual
defects, inadequate eye fluids and tears.
WHERE THINGS GO WRONG
1.Eccrine Glands: Sweat Glands/ Sebaceous Glands(skin):
Decreased or absent sweating. Often, the first clue that the sweat glands
are absent or not functioning properly is an elevated temperature. This is
the result of sweat glands that function at various levels. Restricted
activity due to heat intolerance is noted.
Dry skin and other chronic skin problems are noted due to
the lack of oil and sweat glands. There is often overgrown dry skin on the
palms of the hands and soles of the feet.
The skin is dark colored and wrinkled over the joints,
primarily over the elbows and knees.
Wrinkled and dark circle around the eyes is also present.
2.Teeth: The main dental manifestation is missing teeth,
varying in severity. Often, the teeth are missing altogether or reduced in
number. There are also other dental manifestations that may be present.
These dental abnormalities are characterized by a variety of developmental
problems. These include underdeveloped teeth and various enamel defects. The
teeth that are present often are discolored, small in height, peg shaped,
pointed, widely spaced, tapered, or malformed. In persons with some types of
ED the enamel covering, that is the outer layer of teeth, is defective.
Without enamel to protect the teeth there may be an excessive number of
cavities.
There may also be cleft palate and/or cleft lip.
3.Musculoskeletal/Jaw bones: If a person never develops
teeth, the alveolar bone, the bone that supports the teeth, never develops.
This creates a condition unfavorable for wearing a complete or partial
denture. It could be concluded that the lack of natural teeth adversely
affects the growth and development of the jaw. Studies show that placing
dental implants in the jaw decreases or stops the bone loss. In some cases
the bone loss is reversed.
4.Hair: The scalp hair is sparse, fine, lightly pigmented,
and abnormal in texture. Often, scanty or total absence of hair is evident.
The hair is also dry because the oil glands are absent or poorly developed.
Sometimes the hair on the scalp appears normal early on but often becomes
thin, sparse, or absent after puberty.
The eyebrows, eyelashes and other body hair may also be
absent or sparse.
5.Fingers, Toes, Nails: Small, extra or absent fingers or
toes may be noted. Small, unusual or slow growing nails are also noted.
Nails may be malformed, thick, discolored, brittle, and hyperconvex or
absent. There is a destruction of the nail matrix, the basic substance that
the nail develops from.
Sometimes the nails fail to grow to the end of the finger.
The nails may be thin and fragile, thick and distorted, brittle and slow
growing. Nails with any of the listed abnormalities may be prone to
infection.
The nail manifestations in the hypohidrotic form of ED are
not as evident as they are in the hidrotic form although they may exist at
various degrees.
6.Ocular/Eye: Few or no tears cause irritation to the
eyes, conjunctivitis, and a sensitivity to sunlight. There may also be
cloudy corneas or cataracts.
Sometimes a condition called strabismus may be evident.
This is an eye condition in which both eyes are crossed.
7.Ear, Nose, Throat and Mucous Glands: The linings of the
nose, larynx, trachea and lungs are normally moistened by various glands. In
ED, these glands may be defective. This generalized underproduction of body
fluids leads to several problems. The decreased number of sweat glands and
mucous glands, along with the absence of the tiny cilia (small hairs), in
the upper respiratory tract and ear canal results in diminished resistance
to infections. This also leads to the mucous secretions of the nose being
exceedingly thick and foul smelling, the secretions also form a crusty mass.
Nasal infections are quite common along with frequent
colds, pneumonia and/or respiratory tract and ear infections.
Saliva is sparse, causing problems with chewing, tasting,
and swallowing foods. There may be yeast infections of the mouth. Nerve or
other deafness may be present. Abnormal ear wax production causes excessive
accumulation of wax in the ear canal. This condition may also lead to
frequent ear infections.
A hoarse and raspy voice is also quite common.
In many cases, affected infants and children may also
exhibit underdeveloped or absent mucous glands within the respiratory and
gastrointestinal (GI) tracts. In some cases, decreased function of certain
components of the immune system (i.e., depressed lymphocyte function,
cellular immune hypofunction), could potentially cause an increased
susceptibility to certain infections and/or allergic conditions. Some people
with ED have abnormal immunoglobulin production. This may be related to the
abnormal mucosa of the gastrointestinal and respiratory tracts. Many
affected infants and children experience recurrent attacks of wheezing and
breathlessness (asthma); respiratory infections; chronic pus-producing
inflammation of the nasal passages; scaling, itchy skin rashes (eczema);
and/or other findings.
8.Other Manifestations: Gonadal abnormalities, unequal
breast development, malformed or absent nipples, mental retardation in
selected patients, as well as recurrent pulmonary infections are often
noted. Feeding problems, poor weight gain, gastroesphophageal reflux,
frequent vomiting or swallowing difficulties may also be present. Patients
usually exhibit a fine smooth dry skin because of the partial or complete
absence of sweat glands. The skin is often lightly pigmented and thin, and
prone to rashes and skin infections. The light skin color makes veins easily
visible.
Facial characteristics are a thick skull bone, under
developed cheekbone, flattened nasal bridge (sometimes called saddle nose),
prominent low-set ears, prominent chin, and thick everted lips.
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