CD-ROM Today 1996 January/CD-ROM Today 1996 January.iso/dp/0343/03439.txt

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$Unique_ID{BRK03439}
$Pretitle{}
$Title{Albinism}
$Subject{Albinism Albinismus Congenital Achromia Hypopigmentation
Oculocutaneous Albinism Tyrosinase Positive Albinism Tyrosinase Negative
Albinism Yellow Mutant Albinism Chediak-Higashi Syndrome Hermansky-Pudlak
Syndrome Cross' Syndrome Brown Albinism Autosomal Dominant Albinism Rufous
Albinism Black Locks-Albinism-Deafness of Sensorineural Type (BADS) Ocular
Albinism Nettleship Falls Syndrome (X-linked) Forsius-Eriksson Syndrome
(X-linked) Aland Island Eye Disease (X-linked) AIED Autosomal Recessive forms
Albinoidism Menkes Disease}
$Volume{}
$Log{}

Copyright (C) 1985, 1989, 1992 National Organization for Rare Disorders,
Inc.

42:
Albinism

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

Synonyms

     Albinismus
     Congenital Achromia
     Hypopigmentation

DISORDER SUBDIVISIONS:

SUBDIVISION I Oculocutaneous Albinism which includes:

     Tyrosinase Positive Albinism
     Tyrosinase Negative Albinism
     Yellow Mutant Albinism
     Chediak-Higashi Syndrome
     Hermansky-Pudlak Syndrome
     Cross' Syndrome
     Brown Albinism
     Autosomal Dominant Albinism
     Rufous Albinism
     Black Locks-Albinism-Deafness of Sensorineural Type (BADS)

SUBDIVISION II Ocular Albinism which includes:

     Nettleship Falls Syndrome (X-linked)
     Forsius-Eriksson Syndrome (X-linked)
     Aland Island Eye Disease (X-linked)
     AIED
     Autosomal Recessive forms

SUBDIVISION III - Albinoidism

     Information on the following diseases can be found in the Related
     Disorders section of this report:

Menkes Disease

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.


Albinism is a group of rare inherited disorders characterized by the
absence at birth of color (pigmentation) in the skin, hair and eyes.
Albinism is also associated with certain syndromes that produce defects in
the eyes (ocular abnormalities).  The syndromes of this disorder are
categorized as Tyrosinase-Negative Oculocutaneous Albinism, Tyrosinase-
Positive Oculocutaneous Albinism (Albinoidism), and Ocular Albinism.

Symptoms

Albinism is a group of rare inherited syndromes characterized by the absence
of color (pigmentation) in the skin, hair and eyes.  In Oculocutaneous
Albinism, the skin and the eyes are generally white.  The symptoms of
Tyrosinase-Negative and Tyrosinase-positive forms of Albinism are similar at
birth.  In both forms newborns typically have pinkish-white skin, white hair
and pink, light gray, blue or hazel eyes.  Those children who are tyrosinase-
positive will eventually develop pigmentation in the skin, hair, and eyes as
they grow older.  Those who have Tyrosine-negative Albinism will not develop
color in their skin, hair or eyes.  Children with both forms of
Oculocutaneous Albinism may experience involuntary rhythmic movements of the
eyes (nystagmus), distorted vision due to an irregular cornea (astigmatism),
crossed eyes (strabismus) and/or nearsightedness (myopia).  Children may also
experience an abnormal sensitivity to light (photophobia).  Squamous cell
carcinomas (a type of skin cancer) may develop in children with
Oculocutaneous Albinism.

Another form of Oculocutaneous Albinism known as Albinoidism or Partial
Albinism has been described.  This form of Albinism is characterized by a
lack of color in the skin (hypomelanism), hair and certain pigmentation
abnormalities of the eye.  Generally other visual defects do not occur.

In Ocular Albinism, the skin and hair are relatively normal but are quite
fair.  Heightened sensitivity to light (photophobia) and the visual
abnormalities of Oculocutaneous Albinism are typically present.  There may be
patchy degeneration of the retina (retinal mosaicism) in the eyes.

The different syndromes of Oculocutaneous Albinism have distinctive
characteristics and symptoms.  Hermansky-Pudlak Syndrome and Chediak-Higashi
Syndrome are two different syndromes of Oculocutaneous Albinism that are
characterized by a loss of pigment.   Other symptoms of Hermansky-Pudlak
Syndrome may include abnormalities of fat (lipid) and platelet storage and/or
one or both eyes being abnormally small (microphthalmos).  There may also be
delayed physical and mental development.  Chediak-Higashi Syndrome is
characterized by abnormalities of the white blood cells (leukocytic disease),
predisposition to infections and a high risk of lymphatic (lymphoreticular)
malignancies.

Types of Ocular Albinism include Nettleship Falls Syndrome (X-linked),
and Forsius-Eriksson syndrome (X-linked).

Causes

Symptoms of Albinism develop due to a lack of the enzyme tyrosinase.  Melanin
is a brown or black pigment that is usually present in the skin, hair and the
iris of the eye.  Tyrosinase is an enzyme that acts to convert tyrosine into
melanin.  Melanin is then stored in special pigment-carrying cells known as
melanocytes.  If tyrosinase is absent and/or does not function properly,
melanin is not incorporated into the melanocytes nor maintained in these
cells.  This results in the absence of color in the skin, hair and eyes.
People with Albinism generally have an even distribution of melanocytes but
the sacs that typically contain the melanin (melanosomes) are empty.

Most of the Oculocutaneous forms of Albinism are inherited as an
autosomal recessive trait.  Partial Albinism or Albinoidism is inherited as
an autosomal dominant trait.  The Ocular types of Albinism may be inherited
as an autosomal dominant, recessive or X-linked genetic traits.  The
defective gene thought to cause Forsius-Eriksson Syndrome or Type II Ocular
Albinism has been located to the short arm of the X chromosome (position 21).

Human traits, including the classic genetic diseases, are the product of
the interaction of two genes, one received from the father and one from the
mother.

In recessive disorders, the condition does not appear unless a person
inherits the same defective gene for the same trait from each parent.  If one
receives one normal gene and one gene for the disease, the person will be a
carrier for the disease, but usually will not show symptoms.  The risk of
transmitting the disease to the children of a couple, both of whom are
carriers for a recessive disorder, is twenty-five percent.  Fifty percent of
their children will be carriers, but healthy as described above.  Twenty-five
percent of their children will receive both normal genes, one from each
parent, and will be genetically normal.

In dominant disorders a single copy of the disease gene (received from
either the mother or father) will be expressed "dominating" the other normal
gene and resulting in the appearance of the disease.  The risk of
transmitting the disorder from affected parent to offspring is fifty percent
for each pregnancy regardless of the sex of the resulting child.

X-linked recessive disorders are conditions which are coded on the X
chromosome.  Females have two X chromosomes, but males have one X chromosome
and one Y chromosome.  Therefore, in females, disease traits on the X
chromosome can be masked by the normal gene on the other X chromosome.  Since
males only have one X chromosome, if they inherit a gene for a disease
present on the X, it will be expressed.  Men with X-linked disorders transmit
the gene to all their daughters, who are carriers, but never to their sons.
Women who are carriers of an X-linked disorder have a fifty percent risk of
transmitting the carrier condition to their daughters, and a fifty percent
risk of transmitting the disease to their sons.

Affected Population

The occurrence of all forms of Albinism is approximately 1 in 10,000 people
in the United States.  Albinism is more common in some isolated communities,
such as the Amish or Mennonite groups in the United States.   Albinism
affects males and females equally except the X-linked forms of this disorder
that affect only males.

Related Disorders

Symptoms of the following disorders can be similar to those of Albinism.
Comparisons may be useful for a differential diagnosis:

Menkes Disease is a rare inherited genetic disturbance of copper
metabolism.  This disorder begins before birth and results in abnormally low
levels of copper in many body tissues.  Changes may occur in the hair, brain,
bones, liver and arteries.  Newborns are often born prematurely and symptoms
may include an abnormally low body temperature (hypothermia), general
weakness, poor appetite and a yellow appearance due to excess amount of bile
in the blood (hyperbilirubinemia or jaundice).  Most newborns with Menkes
Disease appear normal and some may have characteristic pudgy cheeks.  At the
age of about 6 weeks, the fine hair of the newborn loses color (pigment).
The hair eventually becomes kinky, tangled and sparse.  Neurological symptoms
usually occur around the age of 1 to 3 months.  These symptoms may include
generalized muscular rigidity, (hypertonia), irritability, feeding
difficulties, convulsions and/or swelling in the brain caused by an
accumulation of blood (subdural hematoma).  Blot clots may also form within
the blood vessels of the brain (cranial thrombosis) and the child may
experience seizures.  Developmental delay is often apparent.  (For more
information on this disorder, choose "Menkes" as your search term in the Rare
Disease Database.)

Therapies:  Standard

There is no cure for the inherited metabolic defect that causes Albinism.
People with Albinism require protection from sunlight, especially for those
people with Oculocutaneous Albinism Syndromes.  Sunglasses, protective
clothing, and sun-protective lotions (containing para-aminobenzoic acid or
PABA) are helpful.  Visual aids may partially correct vision.  Surgery to
correct an eye that is either crossed or looking away (strabismus) may offer
cosmetic results but no improvement in vision due to the abnormalities of the
optic nerve.  Treatment of other features of the various types of Albinism is
symptomatic.  In Chediak-Higashi Syndrome, it is reported that high doses of
ascorbic acid may reduce some consequences of the lipid (fat-like substances)
storage defects.

Genetic counseling will be of benefit for patients and their families.

Therapies:  Investigational

Research and further study of Albinism is underway.

Research on genetic defects and their causes is ongoing.  The National
Institutes of Health (NIH) is sponsoring the Human Genome Project that is
aimed at mapping every gene in the human body and learning why they sometimes
malfunction.  It is hoped that this new knowledge will lead to prevention and
treatment of genetic disorders in the future.

This disease entry is based upon medical information available through
October 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 Albinism, please contact:

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

     National Organization for Albinism and Hypopigmentation (NOAH)
     1599 Locust St., Suite 1816
     Philadelphia, PA  19102
     [phone]

     NIH/National Institute of Child Health and Human Development (NICHD)
     9000 Rockville Pike
     Bethesda, MD  20892
     [phone]

For Genetic Information and Genetic Counseling Referrals:

     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
     301-652-5553

References

THE MERCK MANUAL 15th ed.  R. Berkow, et al., eds; Merck, Sharp & Dohme
Research Laboratories, 1987.  Pp. 2084, 2299.

MENDELIAN INHERITANCE IN MAN, 10th Ed.:  Victor A. McKusick, Editor:
Johns Hopkins University Press, 1992.  Pp. 1202-1207.

THE METABOLIC BASIS OF INHERITED DISEASE, 6th Ed.:  Charles R. Scriver, et
al., Editors; McGraw Hill, 1989.  Pp. 2915-2922.

CECIL TEXTBOOK OF MEDICINE, 19th Ed.:  James B. Wyngaarden, and Lloyd H.
Smith, Jr., Editors; W.B. Saunders Co., 1990.  Pp. 2322-2323.

BIRTH DEFECTS ENCYCLOPEDIA, Mary Louise Buyse, M.D., Editor-In-Chief;
Blackwell Scientific Publications, 1990.  Pp. 69-81.

GENETIC MAPPING OF X-LINKED ALBINISM-DEAFNESS SYNDROME (ADFN) TO Xq26.3-
q27.  I.Y. Shiloh, et al.; Am J Hum Genet (Jul 1990; issue 47 (1)):  Pp. 20-
27.

THIOREDOXIN REDUCTASE ACTIVITY IN HERMANSKY-PUDLAK SYNDROME:  A METHOD FOR
IDENTIFICATION OF PUTATIVE HETEROZYGOTES.  K.U. Schallreuter and C.J. Witkop;
J Invest Dermatol (March 1988; issue 90 (3)):  Pp. 372-77.

A FREQUENT TYROSINASE GENE MUTATION IN CLASSIC, TYROSINASE-NEGATIVE (TYPE
IA) OCULOCUTANEOUS ALBINISM.  L. B. Giebel, et al.; Proc Natl Acad Sci USA
(May 1990; issue 87 (9)):  Pp. 3255-58.

ALBINISM.  J.W. Harfemeyer; J Ophthalmic Murs Technol (Mar-Apr 1991; Issue
10(2):  Pp. 55-62.