Haemaglobin Bart's in cord blood of Malaysians.

In the newborn the diagnosis of alpha thalassaemia trait is easier because of the presence of haemoglobin Bart's (Hb Bart's). Alpha thalassaemia is common in Southeast Asia. Malaysians are composed of the ethnic groups Malays, Chinese, Indians and Eurasians. Hb Bart's itself is not a simple inherited character but arises from genetically determined imbalance in the biosynthesis of alpha and non alpha chains. 58% of the cord blood samples tested showed raised levels of Hb Bart's. In the Chinese the most common cause of hereditary haemolytic anaemia is haemoglobin H and hydrops foetalis is seen. The rare occurrence of these syndromes in the Malays and Indians in spite of the presence of Hb Bart's indicates an altered expression of the alpha thalassaemia gene in these populations.