Background: The interaction of the non-deletional α
+thalassaemia mutations Haemoglobin
Constant Spring and Haemoglobin Quong Sze with the Southeast Asian double α-globin gene deletion
results in non-deletional Haemoglobin H disease. Accurate detection of non-deletional Haemoglobin
H disease, which is associated with severe phenotypes, is necessary as these mutations have been
confirmed in the Malaysian population.
Methods: DNA from two families with Haemoglobin H disease was extracted from EDTA-
anticoagulated whole blood and subjected to molecular analysis for α-thalassaemia. A duplex
polymerase chain reaction was used to detect the Southeast Asian α-globin gene deletion. Polymerase
chain reaction-restriction fragment length polymorphism analysis was then carried out to determine
the presence of Haemoglobin Constant Spring and Haemoglobin Quong Sze. A combine- amplification
refractory mutation system protocol was optimised and implemented for the rapid and specific
molecular characterisation of Haemoglobin Constant Spring and Haemoglobin Quong Sze in a single
polymerase chain reaction.
Results and Conclusions: The combine-amplification refractory mutation system for
Haemoglobin Constant Spring and Haemoglobin Quong Sze, together with the duplex polymerase
chain reaction, provides accurate pre- and postnatal diagnosis of non-deletional Haemoglobin H
disease and allows detailed genotype analyses using minimal quantities of DNA.
