Ectodermal dysplasia is a large group of inherited disorders characterised by a primary defect in hair, teeth, nails or sweat gland function, in addition to another abnormality in any tissue of ectodermal origin. These are ears, eyes, lips, mucous membranes of the mouth or nose, and the central nervous system. Despite some of the syndromes having different genetic causes, the symptoms are sometimes very similar. Diagnosis is usually by clinical observation, often with the assistance of family medical histories so that it can be determined whether transmission is autosomal dominant or recessive.

1. ECTODERMAL
DISPLASIA

2. Noman Saeed
BS-Zoology 2016-20
Department of Zoology
The University of Azad Jammu and Kashmir,
Muzaffarabad
NomanSaeed492@gmail.com

3. CONTENTS
• Introduction
• Prevalence
• Causes of Ectodermal Dysplasia
• Classification
• Genetics of ED
• Pedigrees
• Clinical Features
• Other Physical Symptoms
• Investigation
• Diagnostic Tests
• Treatments

4. Introduction
• Ectodermal Dysplasia Is not a single disorder but a
group of genetic syndromes all deriving from
abnormalities of the ectodermal structures.
Ectodermal Dysplasia
Ectoderm Dysplasia
Outer Most Layer of Cells In
Embryonic Development
Developmental abnormality

5. Prevalence
•The incidence in male is estimated at 1 in
100,000 births.
•The carriers-incidence is probably around
17.3 in 100,000 women.

6. Causes of Ectodermal Dysplasia
• Mutation or deletion of certain genes
located on different chromosomes.
• EDs are caused by a genetic defect.
They can be inherited or passed down
the family line.
• In some cases, they can occur in
people without a family history of the
condition, in which case a de Novo
mutation has occurred.

7. Classification
•More than 150 different syndromes have been
identified
•Different subgroups are created according to the
presence or absence of the four primary
ectodermal dysplasia (ED) defects:
ED1: Trichodysplasia (hair dysplasia)
ED2: Dental dysplasia
ED3: Onychodysplasia (nail dysplasia)
ED4: Dyshidrosis (sweat gland dysplasia)

8. Genetics of ED
• The ED are caused by alterations in genes
• Altered genes may be inherited from a parent
• Normal genes may become altered (mutate) at the time of egg or
sperm formation or after fertilization
• Chances for parents to have affected children depend on the
inheritance pattern of the type of ectodermal dysplasia

9. Autosomal Dominant ED
• When the ED is an autosomal dominant trait, the
parent who is affected has a single copy of the
abnormal gene and may pass it on to his or her
children
• Regardless of the gender of the parent or the child,
there is a 50% chance for each child
• All children who receive the abnormal gene will be
affected

10. Autosomal Dominant ED

11. Pedigree Autosomal Dominant ED
Affecte
d
Deceas
ed
I
III
II
Example: Epidermolysis Bullosa (Some Forms)

12. Autosomal Recessive ED
• When the ectodermal dysplasia in the family is an autosomal
recessive trait, the usual situation is that each parent is
unaffected
• The parents are said to be carriers
• They each have a single copy of the abnormal gene
• the chance for them to have another affected child is 1 in 4
• 1 in 4 children get a copy of the abnormal gene from each
parent and is affected
• 2 in 4 gets only one copy each and are carriers
• the remaining 1 in 4 inherits a normal gene from each parent
and is not affected

13. Autosomal Recessive ED

14. Pedigree of Autosomal Recessive
ED
Carrier
Affected
Deceased
I
II
III
IV Example: Phenylketonuri

15. X-Linked Recessive ED
• If a woman is a carrier of an X-linked recessive disorder there is
a 50% chance that each male child will receive the abnormal
gene and be affected
• 50% chance that each female will receive the abnormal gene
and be a carrier (like the mother).
• If a man has the abnormal gene he is affected and will pass the
gene on to all of his daughters. The daughters will be carriers
• Since the gene is on the X chromosome, sons will not be
affected because they receive the mans Y chromosome

16. X-Linked Recessive
ED

17. Pedigree of X-Linked Recessive ED Carri
er
Affecte
d
Deceas
ed
I
II
III
IV
Example: Fabry’s Disease

18. Clinical Features
•Ectodermal dysplasia typically affects the four
organs primarily
• Hairs
• Nails
• Teeth
• Sweat Glands

19. Hairs ED
•Scalp and body hair may be thin, sparse, and light
in color.
•Hair may be coarse, excessively brittle, curly or
even twisted.

20. Nails ED
• Fingernails and toenails may be thick, abnormally
shaped, discolored, ridged, slow growing, or brittle.
• •Sometimes nails may be absent.
• Cuticles may be prone to infection.

21. Teeth ED
• Abnormal tooth development
resulting in missing teeth or growth
of teeth that are peg-shaped or
pointed.
• •Tooth enamel is also defective.
• Dental treatment is necessary and
children as young as 2 years may
need dentures.

22. Sweat Glands ED
• Eccrine sweat glands may be absent or
sparse so that sweat glands function
abnormally or not at all.
• Without normal sweat production, the body
cannot regulate temperature properly .
• Children may experience recurrent high
fever that may lead to seizures and
neurological problems.
• Overheating is a common problem,
particularly in warmer climates.

23. Other Physical Symptoms
• Lightly pigmented skin, in some cases red or brown pigment
may be present.
• Skin may be dry and is prone to rashes and infection.
• Abnormal ear development may cause hearing problems.
• Cleft palate/lip.
• Missing fingers or toes (digits).
• Respiratory infections due to lack of normal protective
secretions of the mouth and nose.
• Lack of breast development.
• Dry eyes occur due to lack of tears. Cataracts and visual defects
may also occur.

24. Investigation
•Radiographs to rule out dental abnormalities.
•Biopsy of the skin – hypothenar eminence is the
most reliable site to demonstrate an absence or
hypoplasia of sweat glands.
•Genetic testing (available for some types of this
disorder).

25. Other Diagnostic Tests
Sweat Glands
Count
Blaschko Lines
Parental Diagnosis – Fetal Skin
Biopsy

26. Treatment
Early dental evaluation
and intervention
Cooling water baths or
sprays may be useful in
maintaining a normal
body temperature.
Wigs may be worn to improve the
appearance of patients with little or
no hair.

27. THANK YOU