Glossary of Hemoglobinopathies 2
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- What is the normal Hb distrib in a healthy adult?
- HbA = 97%
HbA2 = 2%
HbF = 1%
- What percentage can HbA2 never be?
- more than 7-10% - there's just not that many delta chains.
- What is the definition of Hbopathy?
- Condition where Hb synthesis is abnormal; Either inherited or genetic mutations.
Result = structural instability or nonfunction of Hb molecule.
- What are 5 ways of having a Hbopathy condition?
- 1. Single or double AminoAcid substitution.
2. Amino acid deletion
3. Decr. Hb chain production
4. Cross-linked or fused Hb
5. Longated subunits
- What are the formal names of
-Decr. Hb chain production
-Cross-linked or fused Hb
-Hb Constant Spring
- What are the 2 types of Hb electrophoresis?
- Cellulose acetate, pH = 8.4
Citrate gel, pH = 6.2
- What is the sequence of migration of Hb in alkaline medium? (moving toward pos)
- C S F A B H
Can santa fly away before halloween?
- What is the sequence of migration of Hb in acid medium?
(moving toward positive, so opposite direction of Alk)
- F A S C
Fast As She Can
- What bands do you seen for Normal patients on
- Alk: Majority is A, small amt A2 on the C band
Acid: All is A
- What bands are seen for a ptnt with Sickle cell Disease?
- Alk: majority at S, some A2 and F
Acid: majority is S, some F
- what is the Hb pattern in S trait?
- Alk: 60% A, 40% S -> biggest bands are A and S, some at C for A2.
Acid: Smaller A band, most S.
- what type of inheritance pattern of sickle cell disease and trait?
- Autosomal co-dominant inheritnc
Disease = homozygous
Trait = heterozygous
- What chromosomes are the Hb genes on?
- 11 and 16
- What Hb genes are on
- 11: 1 Beta, 2 Gamma, 1 epsilon, 1 delta.
16: 2 zeta, 2 epsilon
- what gene/s is/are altered in sickle cell anemia?
- the beta gene on chrom 11
- why is there a 60/40 ratio of normal to abnormal Hb in Sickle cell trait?
Why doesn't Disease?
- because normal has a higher Hb affinity
b/c all the Hb in disease is HbS and there are no normal B chains.
- What occurs in Sickling phenom?
- 1. Due to decreased O2 affinity, deoxygenation -> incr. viscosity
2. RBCs less pliable; plug up circulation.
3. Plug causes more deoxygen.
4. Tactoid bars form - 15 Hb molecules per bar.
5. Tactoid bars sickle cells and block vessels.
6. Ischemic infarct results
7. Result: pain, tissue death
- What is a thrombotic sickle crisis?
- an Aplastic crisis due to viral infections (they change pH), causing hemolysis of the sickled cells.
- What is the occurence of SS dis?
- Worldwide is 1/500
U.s. is 1/1875 Afric.Americans
- what causes sickling to be irreversible?
How does sickling alter lifespan of RBC?
- if cells are sickled 7 to 8 x.
Life = 14-17 days inst. of 120
- What are 5 clinical features of SS disease?
1. Fatigue, jaundice, leg ulcer
3. Joint pain
4. Aplastic crisis
5. sickling crisis - bact. inf
- What are the 4 major lab findings in SS disease?
- 1. Severe hemolytic N/N anemia
3. Erythroid hyperplasia
4. Evidence of free Hb and Red cell destruction
- Waht are 5 steps in diagnosing SS disease?
- 1. Physical symptoms/PBS
2. Hb Solubility test
3. Urea solubility test
4. Hb Electrophoresis - BEST
5. Sickle cell prep
- what is the normal electroph pattern of a 6 mo old or younger?
- Some HbA but still a lot of HbF - it is the FETAL Hb.
- What 6 ways can one treat SS disease?
- 1. Administer O2 - prevent sckl
3. Transfuse - esp infants.
4. Support - iron chelate/pain
5. Prevent sickling inducement
6. Bone marrow transplant - only cure
- What happens w/ the iron in SS disease patients?
- They get hemociderosis -> iron overload b/c they're not using it.
- What are some complications of SS disease, sickle cell anemia?
- 1. Adapt to Anemia -> it's hard on the heart and decr. lifespan.
2. Crisis causes organ failure, thrombosis/hemorrhage, and death.
- in what population is sickle cell trait found?
- 9% of Afr. Americans
Asian indians, Turks, Arabs, Greeks, Italians.
- What are the clinical features of SS trait - how does it compare anemia-wise to SS dis?
- Asymptomatic and benign, with rare crises.
Not detected unless screen for HbS.
- What type of patient alterations does SS trait cause?
- NOT MUCH!
-Wil have a Normal lifespan.
-May have a few sickle crises.
- What does the PBS show in SS trait?
What other lab tests diagnose?
- -Moderate target cells
-Solubility test positive
-60% A1, 40% S, 3% HbA2
- What type of inheritance pattern is seen in HbC disease?
What's an interesting feature?
- Non-sex linked Incomplete dominant.
Male:Female is 3:1
- What nationalities is HbC disease seen in most?
- Afr.Americans - 2,3%
Native W. Africans - 20-30%
- How does HbC disease anemia compare to HbS?
- It's less common
Milder anemia, but might have marked splenomegaly.
- Why does splenomegaly develop in HbC disease?
- HbC crystals are made, and the spleen attempts to keep them.
- What lab information indicates HbC disease?
- PBS: N/N mild anemia
Mkd Target cells, Spherocytes, Folded cells, HbC crystals.
- What is necessary for forming HbC crystals?
What causes it?
- 40% HbC in the cell.
caused by Dehydration
- What is the electroph. pattern of Hb C disease?
- 90% HbC
HAVE TO USE ACID to seperate the C from EAO on alkaline.
- What is the treatment/therapy for HbC disease?
- -Know the limitations - prevent dehydration, excess heat/vomit.
-Careful in pregnancy/stress.
Relatively normal lifespan.
- What are te lab findings of HbC trait?
What type of anemia?
- Benign anemia, maybe absent.
- What is the electroph pattern of HbC trait?
- 35-45% HbC
55-65 HbA1 (higher affinity)
- Regarding Hb SC disease:
-3 clinical features/problems
- As common as HbS disease
Mild anemia, less severe than HbC disease
1. Hemolytic Crisis
3. Pregnancy problems
- What are lab findings in HbSC disease?
- PBS shows MARKED Targets
FEW sickles, SC crystals
-polychromasia and nRBCs.
- what's the electroph pattern of Hb SC disease?
- -Half/half HbS & HbC
-maybe a little HbF
-make sure to do acid so C seperates out.
- what Hbopathy/Thalassemia combos should you know about?
- HbS/Beta thal
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