Question 1

Which of the following best describes the genetic inheritance pattern of sickle cell disease (SCD)?

Accepted Answer

Autosomal recessive

Question 2

What is the specific amino acid substitution responsible for sickle cell disease in the β-globin chain?

Accepted Answer

Glutamic acid to valine at position 6 ($\mathrm{E6V}$)

Question 3

Which laboratory technique is commonly used to diagnose sickle cell disease by separating hemoglobin variants?

Accepted Answer

Gel electrophoresis

Question 4

A child inherits one sickle cell allele ($\mathrm{HbS}$) from one parent and one normal allele ($\mathrm{HbA}$) from the other. What is the most likely phenotype?

Accepted Answer

Sickle cell trait

Question 5

Which of the following best explains why sickle cell disease is more prevalent in certain geographic regions?

Accepted Answer

Selective advantage against malaria in heterozygotes

Question 6

What is the primary molecular consequence of the $\mathrm{E6V}$ mutation in the β-globin chain?

Accepted Answer

Formation of a hydrophobic pocket

Question 7

Which form of hemoglobin is associated with the deoxygenated state and promotes sickling in SCD?

Accepted Answer

T (Tense or Taut) form

Question 8

A patient with sickle cell disease presents with acute pain and swelling in the hands and feet. What is the most likely diagnosis?

Accepted Answer

Dactylitis (Hand-Foot Syndrome)

Question 9

Which of the following treatments increases the production of fetal hemoglobin ($\mathrm{HbF}$) in patients with sickle cell disease?

Accepted Answer

Hydroxyurea

Question 10

Why does fetal hemoglobin ($\mathrm{HbF}$) ameliorate the symptoms of sickle cell disease?

Accepted Answer

HbF has a higher affinity for oxygen, preventing sickling

Question 11

Which gene regulatory factor is known to suppress fetal hemoglobin ($\mathrm{HbF}$) expression in adults?

Accepted Answer

BCL11A

Question 12

A couple, both carriers of the sickle cell trait ($\mathrm{HbA/HbS}$), have a child. What is the probability that their child will have sickle cell disease ($\mathrm{HbS/HbS}$)?

Accepted Answer

$\frac{1}{4}$

Question 13

Which of the following is a potential risk associated with gene therapy for sickle cell disease?

Accepted Answer

Unintended mutations in non-target genes

Question 14

Which clinical symptom is commonly associated with the blockage of capillaries by sickled red blood cells?

Accepted Answer

Acute pain crisis (vaso-occlusive crisis)

Question 15

Which historical event marked the first description of sickle cell disease?

Accepted Answer

Report on Walter Clement Noel's blood in 1904

Question 16

Which of the following best explains the mechanism by which the $\mathrm{E6V}$ mutation leads to sickling of red blood cells?

Accepted Answer

Hydrophobic interactions cause hemoglobin polymerization under low oxygen

Question 17

A patient with sickle cell disease undergoes DNA testing. Which result would confirm the diagnosis?

Accepted Answer

Detection of a missense mutation changing codon 6 from GAG to GTG in the β-globin gene

Question 18

Which of the following is NOT a typical clinical consequence of sickle cell disease?

Accepted Answer

Hypertension

Question 19

Which of the following approaches is currently being explored as a gene therapy for sickle cell disease?

Accepted Answer

Insertion of a normal β-globin gene using a viral vector

Question 20

Which factor is known to regulate the expression of fetal hemoglobin ($\mathrm{HbF}$) and is a target for new therapies in SCD?

Accepted Answer

BCL11A

Sickle Cell Disease: Genetics, Pathophysiology, and Clinical Aspects

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