Hemoglobinopathies Flashcards
Alpha and Zeta globin genes can be found in what chromosome?
Chromosome 16
Beta and epsilon globin genes can be found in what chromosome?
Chromosome 11
Gamma and delta globin genes can be found in what chromosome?
Chromosome 11
What is the first hemoglobin formed during the fetal life? What globin chains makes the hemoglobin?
Gower 1
Zeta + epsilon
Gower 2 is composed of what globin chains?
Alpha + epsilon
Portland is composed of what globin chains?
Zeta + gamma
Hemoglobin F is composed of what globin chains?
Alpha + gamma
What is the predominant hemoglobin at birth?
Hemoglobin F
Two years after birth, what is the predominant hemoglobin present? What hemoglobin chains is it made of?
Hemoglobin A
Alpha + Beta
Modified true or false:
Hb A migrates differently than Hb S when subjected to electrophoresis
True
SCD is caused by what type of mutation and where doea it occur?
Point mutation
Nucleotide 17, position 6
What amino acid is replaced in SCD? What is the amino acid present instead?
Glutamic Acid
Valine
What causes the hemoglobins to interact with each other in SCD
Due to the exposed hydrophobic regions
How does the increase in 2,3-BPG affect oxygen tension?
Decreases oxygen tension, releases the O²
Other reasons affecting the sickling process
• Level of intracellular hydration
• Rediatribution of phospholipids in the RBC membrane
• microparticles, or “cellular dusts”
What are the clinical features of SCD?
• vasooclusion
• bacterial infections
• hematologic defects
• cardiac defects
• high-risk pregnancy
• stunted growth
What is the hallmark of SCD?
Vasooclusion / vasooclusive crisis
Bodies present in the PBS of autosplenectomy
Howell-jolly bodies
Pappenheimer bodies
What illness due to SCD displays as pulmonary infiltrates on chest radiograph?
Acute chest syndrome
Blood picture of SCD
Normocytic, normochromic
RDW of SCD
Increased
What is the most common test in checking for Hb S? State the positive and negative results.
Hemoglobin solubility test
Turbid = +
Clear = -
False positive results on hemoglobin solubility test are caused by:
Hyperlipidemia
Few rare hemoglobinopathies
Too much blood added
False negative results on hemoglobin solubility test are caused by:
Infants younger than 6 months
Low Hct
What is the common first step in confirming hemoglobinopathies
Alkaline hemoglobin electrophoresis
What hemoglobin quantification method is best used for thalassemias?
HPLC (High Performance Liquid Chromatography)
A confirmatory techinque for hemoglobin, but expensive and complex
Isoelectric focusing
What are the techniques used for neonatal screening?
IEF
HPLC
Reversed-phase HPLC
Heterozygous state are ______
Symptomatic or asymptomatic
Asymptomatic
Hemoglobin solubility test result for Hb AS
Positive
What happens to the glutamic acid in Hemoglobin C?
Turns to lysine
Clinical symptoms of Hb C
Milder compared to SCD
Mild splenomegaly
No VOC
Asymptomatic
Blood picture of Hb C
Normocytic, normochromic
Hexagonal crystals within RBCs may be seen in what hemoglobin?
Hb C
Hemoglobin solubility test result for Hb C
Negative
Techniques used for the definitive diagnosis of Hb C
Electrophoresis
HPLC
Nucleic acid testing
Hb C-Harlem is caused by a mutation in what position?
Position 73
Aspartic acid to asparagine
Hemoglobin solubility test result for Hb C-Harlem
Positive
What is changed in Hb E, and at what position?
Glutamic acid to lysine, position 26
Hemoglobin solubility test result for Hb E
Negative
