Human Genetics

Question 1

Which chromosome contains the allele for the a-globin cluster?

Answer 1

16

Question 2

Which chromosome contains the allele for the b-globin cluster?

Answer 2

11

Question 3

Describe sickle cell anaemia.

Answer 3

Qualitative Hemoglobinopathies.
Autosomal Recessive.
Affects the b chain, characterized by amino acid substitutions.
In deoxygenated environments, the RBC polymerized.
Sickle, rigid, stuck in small vessels

Question 4

What is the genetic mutation in sickle cell disease?

Answer 4

HBB c.20A>T p.Glu6Val

Question 5

What is thalassemia?

Answer 5

Are hereditary abnormalities of haemoglobin production in which the primary difficulty is a quantitative deficiency of either the a or b globins.

Question 6

Describe the pathogenicity of a-Thalassemia.

Answer 6

A mutation in the alpha genes on chromosome 11.
1- carrier (asym)
2- a thalassemia minor (asym)
3- HBH disease (sym)
4- Hb Barts (fatal- Hydrops fetalis)

Question 7

Describe the pathogenicity of b-Thalassemia.

Answer 7

Deficient production of β-globin chains leads to the accumulation of excess α-globin tetramers in erythroid cells.
Free α-globin protein is unstable and generates cytotoxic reactive oxidant species and cellular precipitates that impair the
maturation and viability of red-cell precursors, resulting in ineffective erythropoiesis and premature hemolysis of circulating
red cell.