Hb H hydrops fetalis syndrome associated with the interaction of two common determinants of a thalassaemia (--^MED / α^TSaudi α)

To date, more than 35 single or oligonucleotide mutations of the α genes that cause α thalassaemia have been described. Their interactions give rise to widely variable clinical manifestations, from a mild hypochromic, microcytic anaemia to a lethal intrauterine anaemia associated with hydrops fetalis. Understanding the molecular genetics enables accurate genotyping, genetic counselling and prenatal testing for the most severe forms of α thalassaemia. Here we show for the first time that the interaction between two relatively common forms of α thalassaemia (--^MED / α^TSaudi α) may be associated with a clinically severe form of α thalassaemia, Hb H hydrops fetalis.