Molecular characterisation of haemoglobin E-Udon Thani (HBB:c.[79G>A;92+7A>G]): a novel form of Hb E-ß-thalassaemia syndrome.

ABSTRACT

Interaction of ßE-globin gene with an in trans ß-thalassaemia gene leads to thalassaemia syndrome, known as haemoglobin (Hb) E-ß-thalassaemia disease, with variable clinical and haematological severity. Here, we reported for the first time the Hb E-ß-thalassaemia syndrome caused alternatively by an in cis interaction of ßE and a novel IVSI#7;A>G mutation, namely the Hb E-Udon Thani (HBBc.[79G>A;92+7 A>G]). The syndrome was found in an adult Thai man (32) who was generally healthy but had an unexplained hypochromic microcytosis. Hb analysis identified heterozygous Hb E with very low Hb E expression (3.1%) and elevated Hb A2 (5.7%). Final diagnosis was made on DNA analysis, which confirmed a double mutation in a single ß-globin gene of the patient. A multiplex allele-specific PCR assay was developed for use in the screening of this novel form of Hb E-ß-thalassaemia in the population.