GENE
DISORDERS
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◌ DR. CHARLES E. SIMMONS
Simmons Pediatrics, Jacksonville, FL
There are many disorders that a person may acquire due to defaults in genes.
The consequences of these genes may appear mild or moderate, or may
have severe or no apparent effect. Right after birth, or early in life, the symptoms may
become obvious. Some are not discovered, however, until adult life. No matter when
they arise, these defective genes have been inherited by the child from their parent.
Gene disorders result in a defect in one or more of the genes that are carried on the
individual chromosomes.
COLOR BLINDNESS
ALBINISM
Albinism is a disorder characterized by a lack of the brown
pigment called Melanin. An
affected individual may have
no pigment in the hair, skin,
and eyes. The hair is usually
white; the skin is pale, and
eyes range from pink to very
pale blue. The eyes are very
sensitive to bright light and
visual impairment is common. Albinism is caused by a
recessive gene, which means
that a child has to inherit a
defective gene from each
parent. The gene causes a
fault in the enzyme that is
responsible for melanin production.
Medical Student
Huntington’s Disease
A person who is color blind
finds it more difficult to disti
guish between the colors red
and green, or the less common blue and yellow pair
because of a defect in the
cones in the retina of the eye.
The disorder is inherited by a
faulty gene carried on the X
chromosome. Usually males
are the victims of being color
blind because they have only
one X chromosome, and the
defect carried is more likely to
be expressed. A female has
two X chromosomes, and a
fault on one chrome some will
be overridden by the other
chromosome. Therefore, the
female becomes the carrier
and never will experience the
color blindness, only males.
This type of inheritance is
called the X-linked recessive,
and there is a 25% chance
that a male will be affected.
Assisted By Dominique D. Barrs
Huntington’s disease causes
involuntary movements, personality changes, and progressive dementia. This is
one disorder that symptoms
usually don’t develop until
over the age of 30 because
deterioration occurs over the
span of 15- 20 years. Huntington’s disease is caused
by an abnormal dominant
gene, therefore each child
has a 1 in 2 chance (50%) of
inheriting the faulty gene.
Sickle Cell Anemia
Hemoglobin, the pigment that gives red blood cells their color, carries oxygen in the blood. When
hemoglobin is deficient or abnormal, the term anemia is used. Therefore, there is a lack of oxygen being supplied to body tissues. There are many forms of anemia, but one found in people
of color is the sickle-cell disease, in which the red blood cells are distorted into a curved sickle
shape. A comparison between the defected sequence and the normal sequence determines the
nature of the amino acid error. This was the way that the molecular basis of Sickle Cell Anemia
was determined, now known to result from a Valine to Glutamine Acid substitution in position 6
of the beta-globin.
GENE
DISORDERS
result in a defect in one or more of the
genes that are carried on the individual
chromosomes
It is vitally important for a mother to receive the proper prenatal and postnatal care to fully understand the risks in possible future generations. Genes are inherited and it is always helpful to be
aware of what genes both the mother and father can give to the offspring. Therefore, the precautions and proper care can be administered.
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MOTHERS DAY
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JANUARY
2015
2014