Transcript Genetic Diseases

Genetic Diseases
(1)Sickle-cell anaemia
鐮刀形紅血球貧血症
Introduction of
Sickle-cell anaemia
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It is a genetic diseases
the patient’s red blood cells are rigid & sickle in
shape
common disaeses in African
two copies of the haemoglobin gene in every cell
of our body
a recessive condition because they have two
copies of the sickle haemoglobin gene to have the
disorder.
Problems of Sickle-cell anaemia
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Less oxygen are be carried
these sickle cell are weak and have shorter
life span
lead to small blood vessels getting blocked
lead to severe pain and damage to organs
such as liver, kidney, lungs, heart and spleen.
Death can be a result.
Explaination of blocking
blood vessels
The Genetic Combination
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(1)Sickle Cell Trait and
Unaffected
 none of the children
will have sickle cell
anaemia.
 a one in two (50%)
chance that any given
child will get one copy
of the HbS gene and
therefore have the
sickle cell trait.
The Genetic Combination
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(2) Sickle Cell Trait
and Sickle Cell Trait
 (25%) chance that any
given child could be
born with sickle cell
anaemia.
 (25%)chance that any
given child could be
completely unaffected
The Genetic Combination
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(3) Sickle Cell Trait
and Sickle Cell
Anaemia
 a one in two (50%)
chance that any given
child will get sickle
cell trait and a one in
two chance that any
given child will get
sickle cell anaemia.
The Genetic Combination
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(4)Sickle Cell
Anaemia and
Unaffected
 all the children will
have sickle cell trait.
 None will have sickle
cell anaemia.
Genetic Diseases
(2) Haemophilia
血友病
Introduction of Haemophilia
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a lifelong inherited genetic disease
Haemophilia (Greek)=“love of blood”
Hemorrhaephilia=“The love of hemorrhage”
(hemorrhage=bleeding)
an essential clotting factor is either partly or
completely missing
causes a patient to bleed for longer than
normal.
Threes types of Haemophilia
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Haemophilia A (80%)
 lacks clotting factor 8
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Haemophilia B(20%)
 lacks clotting factor 9
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Haemophilia C
 lacks clotting factor 11
Why Haemophilia patient
bleeding seriously
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For blood
clotting,
 13 clotting
factors
(protein),must be
all present,blood
can’t clot,even
lack of one.
Levels of Haemophilia
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First level of
Haemophilia
 5%~30% of clotting
factors in blood
 only get problem
when serious injury or
during operation.
(Cont’d)Levels of Haemophilia
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Second level of Haemophilia
1%~5% clotting factors in blood
regular bleeding(spontaneous)
Third level of Haemophilia (severe)
<1% clotting factors in blood
bleeds cause acute pain and severe joint
damage leading to disability
Causes of Haemophilia
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Inheritance
 the problem
gene(production of
clotting factors) is
in X chromosome
 Most patients are
Male
 because they only
got one Xchromosome
Causes of Haemophilia
Causes of Haemophilia
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Acquired Haemophilia
not born with haemophilia develop
antibodies against one of the clotting factors
such as factor 8
Pregnancy and autoimmune diseases such
as rheumatoid arthritis and cancer may
increase the risk of developing it(antibodies)
Treatments of Haemophilia
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replacement of the missing clotting factor.
injecting it on a regular basis (called
prophylaxis) to help prevent bleeding
(Regular treatment )
injecting at the time a bleed occurs (called
on-demand therapy)
no permanent way of replacing or
increasing the clotting factor level.
Genetic Diseases
(3)G-6-P dehydrogenase Deficiency
葡萄糖-6-磷酸鹽去氫酉每缺乏症
Introduction of G-6-P Deficiency
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glucose-6-phosphate dehydrogenase
deficiency (favism)
is a hereditary abnormality in the activity of
an erythrocyte (red blood cell) enzyme
lead to hemolytic anemia with jaundice
following the intake of fava beans, certain
legumes and various drugs
Inheritance of G-6-P Deficiency
Inheritance of G-6-P deficiency
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The defect is sex-linked, transmitted from
mother (usually a healthy carrier) to son (or
daughter, who would be a healthy carrier.
This is due to the fact that the structure of
G-6-PD is carried on the X chromosome
Symptoms of G-6-P Deficiency
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hemolytic anemia:feel tired, short of breath, have
an irregular heart beat, and may have a dark
orange urine.
 This enzyme is essential for assuring a normal life
span for red blood cells, and for oxidizing
processes. This enzyme deficiency may provoke
the sudden destruction of red blood cells and lead
to hemolytic anemia with jaundice
Treatment of G-6-P deficiency
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Avoid taking fava beans, certain legumes
and various drugs e.g. Chloramphenicol
Blood transfusions when crisis appear
Conclusion
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For the above three genetic diseases
There is no cure for them
thus to avoid these disease
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Genetic test should be done before
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marriage