Transcript Sickle Cell Disease

Sickle Cell Disease
Hemoglobin



Protein made of many amino acids
The sequence of amino acids is
genetic coded by DNA
Function to carry oxygen and other
compounds
Genetic Process



DNA contains compounds called bases–
adenine, thymine, guanine and cytosine– in
a genetic coded sequence
mRNA– matches up to those bases and
reads the message– where an
adenine/thymine, guanine/uracil etc
Moves to cytoplasm of cell and waits for tRNA carrying the amino acid to find the right
sequence and drop off its amino acid
www.vcbio.science.ru.nl/ images/cellcycle/mcel...
http://fig.cox.miami.edu/~cmallery/150/chemistry/hemoglobin.jpg
Normal Pathology



Inherit 2 copies of the gene called
Alleles
When born have Hemoglobin F
By 3 months replaced by Hemoglobin
A
Sickle Cell




Caused by a SNP– single nucleotide
polymorphism
DNA has Adenine (A base) replaced by
Thymine (T base)
So Code is GTG instead of GAG
Valine get put in place of Glutamic acid
in 6th amino acid of both beta chains
Sickle Cell continued



Under certain conditions such as low
O2 , the hemoglobin molecules stick
together or polymerize
Stretches the Red Blood Cells to look
like a “sickle”
Affects about 8-11% of African
Americans
http://www.healthsystem.virginia.edu/internet/hematology/HessImag
es/Sickle-Cell-Disease-40x-website.jpg
Problems








Cells can’t move thru microvessels
Blood get thick or viscous
Spleen removes the defective cells
Stroke
Infections
Difficulty breathing
Pain
Organ failure or damage
Treatment



Antibiotics started very early in children
Transfusions
Drugs to Aid in production of Hemoglobin F


Hydroxyurea
Butyrate



IV dose and oral 30-40 tablets per day
Pulse therapy
Bone Marrow Transplantation