Molecular Identification of a Rare Haemoglobin Variant: Hb G Coushatta in Malaysia

Authors

  • Alifah Nadia Abu Hassan Institute for Medical Research
  • Ezalia Esa Institute for Medical Research
  • Nur Aisyah Aziz Institute for Medical Research
  • Faidatul Syazlin Abd Hamid Institute for Medical Research
  • Siti Aisyah Lazim Hospital Raja Permaisuri Bainun, Ipoh, Perak
  • Zubaidah Zakaria Institute for Medical Research

Keywords:

Haemoglobin variant, Hb G Coushatta, molecular analysis.

Abstract

Thalassaemia screening programme was conducted to reduce the burden of the disease [1]. Here, we describe one unexpected discovery in a 33-year-old gentleman and also the importance of DNA analysis in detecting the globin gene mutation. 

Case report:

A male patient was screened for haemoglobin (Hb) variant after his wife was noted to have beta thalassaemia trait during her antenatal checkup. Otherwise, he was asymptomatic. He had a normal Hb (16.09 g/L), an increased red blood cell (RBC) count (5.91x10^6/μL) with a borderline mean corpuscular volume (80.7 fL) and a borderline mean corpuscular haemoglobin (27.1 pg). The RBCs on peripheral blood smear, appeared hypochromic microcytic. A prominent band was seen at the S region on alkaline Haemoglobin electrophoresis (Fig. 1), which was not showed in the high performance liquid chromatography. Instead, there was a significant increase in Hb A2/E (42.7%), a great reduction in Hb A (45.6%) and normal Hb F value (0.3%). 

In capillary electrophoresis, an abnormal peak was observed in Hb D zone (40.8%) with normal Hb A2 (2.6%) The screening methods would indicate Hb E, Hb D or Hb S. But none of these were shown by at least two of the methods. Therefore, beta-globin gene sequencing was carried out, which revealed Hb G Coushatta mutation [β22(B4)(GAA→GCA)] (Fig. 2).

Hb analysis may be useful in quantifying the Hb variant. However, definitive diagnosis by molecular analysis is required for identifying the rare mutation such as Hb G Coushatta. Although the variant carries no significance in clinical manifestations [2], it is still important to identify the rare mutation as it can be passed on to the next generation and may evolve to different haplotypes.

 

 

Author Biographies

  • Alifah Nadia Abu Hassan, Institute for Medical Research

    Haematology Unit, Cancer Research Centre, Institute for Medical Research, Jalan Pahang, 50588, Kuala Lumpur, Malaysia

  • Ezalia Esa, Institute for Medical Research

    Haematology Unit, Cancer Research Centre, Institute for Medical Research, Jalan Pahang, 50588, Kuala Lumpur, Malaysia

  • Nur Aisyah Aziz, Institute for Medical Research

    Haematology Unit, Cancer Research Centre, Institute for Medical Research, Jalan Pahang, 50588, Kuala Lumpur, Malaysia

  • Faidatul Syazlin Abd Hamid, Institute for Medical Research

    Haematology Unit, Cancer Research Centre, Institute for Medical Research, Jalan Pahang, 50588, Kuala Lumpur, Malaysia

  • Siti Aisyah Lazim, Hospital Raja Permaisuri Bainun, Ipoh, Perak

    Haematology Unit, Pathology Department, Hospital Raja Permaisuri Bainun, Jalan Hospital, 30990 Ipoh, Perak, Malaysia

     

     

  • Zubaidah Zakaria, Institute for Medical Research

    Haematology Unit, Cancer Research Centre, Institute for Medical Research, Jalan Pahang, 50588, Kuala Lumpur, Malaysia

References

Ezalia, et. al., Thalassaemia Screening among Healthy Blood Donors in Hospital Tengku Ampuan Rahimah, Klang. Med & Health, 2014. 9(1): p. 44-52.

Steinberg, M. H., et. al., Disorders of Haemoglobin: Genetics, Pathophysiology, and Clinical Management. Cambridge University Press, 2009. p. 600-601.

Downloads

Published

2018-02-02

Issue

Section

Extended Abstracts for GG2020 Conference 2017