Haemoglobin H disease due to (--(SEA)) alpha-globin gene deletion and alpha 2-codon 30 (Delta GAG) mutation: a family study

A Chinese family in which two siblings suffer from haemogloblin (Hb) H dise ase due to (--(SEA)) alpha -globin gene deletion and alpha2-codon 30 (Delta GAG) mutation is described. Both siblings are transfusion-independent and have survived to adulthood. in contrast to previous report of hydrops fetal is associated with zeta-alpha -thal-1 and alpha2-codon 30 (Delta GAG) mutat ion, the zeta -globin genes are intact in the two siblings, which most prob ably alleviates the gamma -chain excess and protects the fetus from severe anaemia. Correlation of genotype with phenotype in Hb H disease is importan t for genetic counselling, especially in the antenatal setting.