Human Genetics Flashcards
Which chromosome contains the allele for the a-globin cluster?
16
Which chromosome contains the allele for the b-globin cluster?
11
Describe sickle cell anaemia.
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
What is the genetic mutation in sickle cell disease?
HBB c.20A>T p.Glu6Val
What is thalassemia?
Are hereditary abnormalities of haemoglobin production in which the primary difficulty is a quantitative deficiency of either the a or b globins.
Describe the pathogenicity of a-Thalassemia.
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)
Describe the pathogenicity of b-Thalassemia.
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.