GENETIC CONTROL OF HEMOGLOBIN SYNTHESIS

GENETIC CONTROL OF HEMOGLOBIN SYNTHESIS

Human globins are encoded by the genes of α and β gene clusters located on chromosome 16 and 11 respectively. The α-like genes include an embryonic gene (ζ) and two adult genes (α₂ and α₁). The β-like genes comprise an embryonic gene (ε), duplicated fetal (γ) and adult (δ and β) genes. 

Adult                                      

HbA₁ = 97%

HbA₂ = 2-3.3%

HbF = 0.1 – 1%

Newborn

HbA₁ = 25%

HbA₂ = <1%

HbF = 75%

Fig: Synthesis of Globin chains variants during prenatal and postnatal life