Introduction
What is hemoglobin?
Hemoglobin is a protein in your red blood cells that carries oxygen to your body’s organs
and tissues and transports carbon dioxide from your organs and tissues back to your
lungs. When at low level, such person is regarded as having anaemia.
Hemoglobin C (HbC) is an abnormal hemoglobin in which glutamic acid residue at the 6th
position of the β-globin chain is replaced with a lysine residue due to a point mutation in
the HBB gene. It produces sickle cell trait but not the disease, as it causes only mild
sickling of the RBCs. It is most common in African-Americans and people of Caribbean,
Italian, and Greek descent also have a higher risk.

People with hemoglobin C trait, or
hemoglobin C carriers, have one gene
for HbC and one normal gene
Their red blood cells contain
both normal
hemoglobin A and also hemoglobin C
Some people with hemoglobin C trait
have slightly more hemoglobin A
than hemoglobin C in their cells.

Symptoms
And Causes
Enlarged spleen.
Gallstones.
Episodes of joint pain.
Increased risk for infection
Fatigue
Pale skin(jaundice)
Visual problems due to retinal changes.
These symptoms are most likely to occur in anemic patient(low red blood
counts)
Hemoglobin C
disease is
inherited. This
means it is passed
down from parents
to children.

Biochemical Basis
The Hb C mutation, β6 Glu → Lys,
GAG → AAG, causes a decrease in
solubility of both the oxygenated and
the deoxygenated forms of the
hemoglobin, resulting in the
formation of crystals instead of long
polymers.
This crystallization results
in membrane damage, red
cell dehydration and shortened red
cell survival, but does not lead to
acute morphological changes
in microcirculation seen in HbS.

Diagnosis And Treatment
The disorder is often found during newborn screening blood tests. These may include:
Complete blood count (CBC):A complete blood count checks the red and white blood cells, blood clotting
cells (platelets), and sometimes, young red blood cells (reticulocytes). It includes hemoglobin and hematocrit
and details about the red blood cells.
Peripheral smear.A small sample of blood is checked under a microscope to see if the cells look normal.
Hemoglobin electrophoresis. This test measures the different types of hemoglobin.
TREATMENT:
Hemoglobin C disease is a chronic condition, but it often doesn’t need any treatment. The anemia that
develops is mild and rarely interferes with everyday life. Neither children nor adults need any special therapy,
vitamins, or iron supplements(folic acid) to treat hemoglobin C disease

Patients with HbSC disease are doubly heterozygous .
They are called compound heterozygotes because
both of their β-globin genes are abnormal, although
different from each other
They inherit Hb C from one parent and Hb S from the
other parent.
A comination of the S and C mutation

Amino acid lysine
replaces the
normal glutamine
in 6th position of
beta chain in Hb C
disease
Amino acid valine
replaces
glutamine in Hb S
Disease
A combination of
these mutations
leads to Hb SC
disease

1. Valine’s side chain is made up entirely of carbon and hydrogen
making it non-polar, while glutamic acid’s side chain has oxygen in it
as well, and is acidic.
2. Lysine is charged like glutamate but it is basic while glutamate is
acidic
3. The substitution in Hb S causes a structural change in beta subunit
that makes it polymerize when deoxygenated. This causes the sickle
shape
4. Sickle cells cause sticking and occlusion

The substation in Hb that causes Hb C causes a structural
change in the beta subunit of haemoglobin that makes it
crystallize in serum
This crystallization reduces the lifespan of the cell but it
doesn’t cause occlusion
The crystallization also causes viscosity of blood because the
crystal structure is denser.

Valine’s side chain is made up entirely of carbon and hydrogen making it non-
polar, while glutamic acid’s side chain has oxygen in it as well, and is acidic.
Lysine is charged like glutamate but it is basic while glutamate is acidic
The substitution in Hb S causes a structural change in beta subunit that makes
it polymerize when deoxygenated. This causes the sickle shape
Sickle cells cause sticking and occlusion

The person with Hb SC has both the Hb C
and Hb S issues but milder than each
because they are heterozygous
They have less crystallization of the RBC and
less occlusion of blood vessels
Common health problems are: anemia and
episodes of fatigue and extreme pain (vaso-
occlusive crisis). The severity of the
symptoms can vary from person to person.

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