CD-ROM Today (UK) (Spanish) 15/CDRT.iso/dp/0369/03693.txt

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$Unique_ID{BRK03693}
$Pretitle{}
$Title{Ectodermal Dysplasias}
$Subject{Ectodermal Dysplasias Anhidrotic X-Linked ED Hypohidrotic ED,
Autorecessive Christ-Siemans-Touraine Syndrome Xeroderma, Talipes, and Enamel
Defect Rosselli-Gulienatti Syndrome Rapp-Hodgekin Hypohidrotic ED
Ectrodactyly-ED-Clefting Syndrome Hidrotic ED Cloustons Syndrome Trichodento
Osseous Syndrome Trichorhinophalangeal Syndrome Ellis-van Creveld Syndrome
(chondroectodermal dysplasia Schopf-Schultz-Passarge syndrome
Dentooculocutaneous Syndrome Odontotrichomelic Syndrome Tooth and Nail
Syndrome Freire-Maia Syndrome Hypoplastic Enamel-Onycholysis-Hypohidrosis
Gorlin's Syndrome Oculodentodigital Syndrome Monilethrix and Anodontia
Oral-Facial-Digital Syndrome (type I) Curly hair-Ankyloblepharon-Nail
Dysplasia Palmoplantar Hyperkeratosis and Alopecia Onychotrichodysplasia with
Neutropenia Facial ED Nail Dystrophy-Deafness Syndrome Triphalangeal
Thumbs-Hypoplastic Distal Phalanges-Onychodystrophy Marshall's ED with Ocular
and Hearing Defects Book Syndrome Chand's ED Hypertrichosis Langinosa
Incontinentia Pigmenti Naegeli Ed Otodental Dysplasia Pachyonychia Congenita
Robinson's ED Stevanovic's ED Witkop ED}
$Volume{}
$Log{}

Copyright (C) 1986, 1988, 1989, 1992 National Organization for Rare
Disorders, Inc.

64:
Ectodermal Dysplasias


** IMPORTANT **
It is possible that the main title of this article (Ectodermal
Dysplasias) is not the name you expected.  Please check the SYNONYM listing
to find the alternate names and disorder subdivisions covered by this
article.

Synonyms

DISORDER SUBDIVISIONS

     Anhidrotic X-Linked ED
     Hypohidrotic ED, Autorecessive
     Christ-Siemans-Touraine Syndrome
     Xeroderma, Talipes, and Enamel Defect
     Rosselli-Gulienatti Syndrome
     Rapp-Hodgekin Hypohidrotic ED
     Ectrodactyly-ED-Clefting Syndrome
     Hidrotic ED
     Cloustons Syndrome
     Trichodento Osseous Syndrome
     Trichorhinophalangeal Syndrome
     Ellis-van Creveld Syndrome (chondroectodermal dysplasia)
     Schopf-Schultz-Passarge syndrome
     Dentooculocutaneous Syndrome
     Odontotrichomelic Syndrome
     Tooth and Nail Syndrome
     Freire-Maia Syndrome
     Hypoplastic Enamel-Onycholysis-Hypohidrosis
     Gorlin's Syndrome
     Oculodentodigital Syndrome
     Monilethrix and Anodontia
     Oral-Facial-Digital Syndrome (type I)
     Curly hair-Ankyloblepharon-Nail Dysplasia
     Palmoplantar Hyperkeratosis and Alopecia
     Onychotrichodysplasia with Neutropenia
     Facial ED
     Nail Dystrophy-Deafness Syndrome
     Triphalangeal Thumbs-Hypoplastic Distal Phalanges-Onychodystrophy
     Marshall's ED with Ocular and Hearing Defects
     Book Syndrome
     Chand's ED
     Hypertrichosis Langinosa
     Incontinentia Pigmenti
     Naegeli Ed
     Otodental Dysplasia
     Pachyonychia Congenita
     Robinson's ED
     Stevanovic's ED
     Witkop ED

General Discussion

** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only.  It should not be used for diagnostic or treatment
purposes.  If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report.


The Ectodermal Dysplasias are a group of hereditary, non-progressive
syndromes in which the affected tissue derives primarily from the ectodermal
germ layer.  The skin, its derivatives, and some other organs are involved.
A predisposition to respiratory infections, due to a somewhat depressed
immune system and to defective mucous glands in parts of the respiratory
tract, is the most life threatening characteristic of this group of
disorders.

Symptoms

Symptoms include eczema, poorly functioning sweat glands, sparse or absent
hair follicles, abnormal hair, disfigured nails, and difficulties with the
nasal passages and ear canals.  Skin is satiny smooth, prone to rashes, and
slow to heal.  Commonly, the teeth fail to develop properly.  Other
complications may include hearing deficit, loss of sight, mental retardation,
limb abnormalities, cleft palate and lip, and urinary tract anamolies.
Allergies are common, as are bronchitis and pneumonia.

The numerous syndromes reported represent different combinations of these
symptoms.  They are traditionally grouped into the anhydrotic and hidrotic
syndromes, according to whether they include the absence or severe deficiency
of sweat glands.  Some significant syndromes include Rapp-Hodgekin
hypohidrotic ectodermal dysplasia, ectrodactyly ectodermal dysplasia,
ectrodactyly-ectodermal dysplasia-clefting syndrome, trichorhinophalangeal
syndrome, oral-facial-digital syndrome, nail dystrophy-deafness syndrome,
trichodento-osseous syndrome, and the Johanson-Blizzard syndrome.

Causes

Ectodermal dysplasias result from faulty development of the ectodermal germ
cell layer during embryogenesis.  Because of the phenomenon of induction,
derivatives of other cell layers may be affected.  The exact genetic and
biochemical defects are unknown, and are thought to vary from one form of the
disorder to another.

The various syndromes have different inheritance patterns.  Anhidrotic
ectodermal dysplasia, for example, involves an X-linked recessive
inheritance, with partial manifestation in females.  (X-linked recessive
traits are expressed predominantly in males.  Females carry the gene on one
of their two X chromosomes.  The second X chromosome will "mask" the trait,
however, if the trait is x-linked recessive.  The trait is expressed in males
because instead of a second X chromosome, they have a Y chromosome which does
not "mask" the harmful gene.  Affected males cannot transmit the trait to
their sons.)  Syndromes with this pattern tend to be more severe.  The Rapp-
Hodgkin Syndrome, by comparison, is an autosomal dominant disorder.  (In
autosomal dominant disorders, a single abnormal gene, contributed by either
parent, "overrides" the normal gene contributed by the other parent causing
disease.  Individuals with one affected parent have a 50% chance of
inheriting the disorder.  Males and females are affected in equal numbers.)

Related Disorders

There is considerable confusion about what should be considered an ectodermal
dysplasia, and what should be excluded from this category.  Many syndromes
involve ectodermal structures, but are progeroid diseases, i.e. they involve
premature ageing.  Others consist of the congenital absences of a single
ectodermally derived structure, such as the pituitary.  Most researchers do
not consider such disorders ectodermal dysplasias.

Therapies:  Standard

No cure for the underlying causes of Ectodermal Dysplasia is known.
Treatment is directed at symptoms.  Over the counter creams may relieve skin
discomfort.  Dentures, hearing aids, etc. may be required.  Heat and over-
exercise are avoided.  Vaccines and anti-infectious agents are used to reduce
infections of skin and respiratory tract.  Cleft palate and lip, syndactyly,
and other limb deformations are treated by surgery.

Genetic counseling is important for Ectodermal Dysplasia patients and
their relatives planning to have children.

Therapies:  Investigational

The National Institute of Dental Research in Bethesda, MD, is conducting a
research project to evaluate dental treatment of individuals who have
Ectodermal Dysplasia.  Treatment will consist of either conventional
removable dentures or fixed dentures supported by dental implants.  The
project is designed to evaluate the effect of dental implants on such things
as satisfaction with treatment, the ability to chew foods and maintenance of
the bone that supports the dentures.  To be eligible to participate in this
study, individuals must have Ectodermal Dysplasia, be missing several teeth,
and between the ages of twelve and seventy years.  A complete oral and dental
examination will be provided to determine if an individual qualifies for the
evaluations for a period of five years.  Financial aid is expected to be
available to help defray travel and lodging expenses for trips to Bethesda,
MD.  For additional information, physicians can contact:

     Albert D. Guckes, M.D.
     Dental Clinic, NIDR
     Bldg. 10, Rm. 6S-255
     National Institutes of Health
     Bethesda, MD  20892
     [phone]
     [phone]

The National Foundation for Ectodermal Dysplasias is conducting a
research project to determine if thermography is a reliable teat to determine
the carrier status for high risk women who have no dental or other anomalies.
A thermography is a diagnostic technique for recording hot and cold areas of
the body by means of infra red scanning.  The amount of sweating in these
areas will be measured.  Patients who are interested in this study may have
their physician contact:

     National Foundation for Ectodermal Dysplasias
     219 E. Main St.
     P.O. Box 114
     Mascoutah, IL  62258-0114
     [phone]

The Human Genetics Branch of the National Institute of Child Health and
Human Development (NICHHD) is conducting a study of X-linked inherited
Hypohidrotic Ectodermal Dysplasia.  This study will attempt to explore how
this disorder affects the hair, nails, teeth, hormonal function, speech,
swallowing, learning, and the production of tears, sweat, and saliva.
Researchers will also measure the levels of epidermal growth factor (EGF) in
various body fluids.  Male patients affected by X-linked Ectodermal Dysplasia
and females that are known carriers may wish to have their physician
contact:

     NIH/National Institute of Child Health and Human Development
     Human Genetics Branch
     Dr. Laura Russell
     Bldg. 10, Rm. 9S242
     Bethesda, MD  20892
     [phone]

This disease entry is based upon medical information available through
December 1992.  Since NORD's resources are limited, it is not possible to
keep every entry in the Rare Disease Database completely current and
accurate.  Please check with the agencies listed in the Resources section for
the most current information about this disorder.

Resources

For more information on Ectodermal Dysplasias, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     [phone]

     National Foundation for Ectodermal Dysplasias
     219 E. Main St.
     Mascoutah, IL  62258
     [phone]

     National Institute of Dental Research
     9000 Rockville Pike
     Bethesda, MD  20892
     [phone]

For information on genetics and genetic counseling referrals, please
contact:

     March of Dimes Birth Defects Foundation
     1275 Mamaroneck Avenue
     White Plains, NY  10605
     [phone]

     Alliance of Genetic Support Groups
     35 Wisconsin Circle, Suite 440
     Chevy Chase, MD  20815
     (800) 336-GENE
     [phone]

References

MENDELIAN INHERITANCE IN MAN, 8th ed.:  Victor A. McKusick; Johns Hopkins
University Press, 1986.  Pp. 215-16, 915.

CECIL TEXTBOOK OF MEDICINE, 18th ed.:  James B. Wyngaarden, and Lloyd H.
Smith, Jr., Eds.:  W. B. Saunders Co., 1988.  Pp. 2347.