The relationship between globin chain synthesis ratios and age in HbE/β thalassemics. γ chain synthesis decreases relative to , and β^E increases relative to  with increasing age. (A) /γ ratios = 8.6 + (0.2 × age), R = .36, P = .029. (B) /β^E = 3.9 − (.029 × age), R = −.47, P = .004.