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An Inherited Genetic Disease

Alpha – Thalassaemia

An Inherited Genetic Disease

Alpha – Thalassaemia
Alpha – Thalassaemia

What is Thalassaemia?

Thalassaemia is an inherited blood disorder that results in impaired production of haemoglobin; the molecule that carries oxygen in the blood.
The disease is genetically inherited from one or both parents as depicted below.

 

Alpha-Thalassaemia

Alpha-Thalassaemia is a form of thalassaemia involving the abnormal copies of HBA1 and HBA2 genes on chromosome 16.

Normal haemoglobin consists of 2 alpha chains and 2 beta chains.

In Alpha-Thalassaemia, there is a decrease in the number of alpha chains, resulting in fewer normal haemoglobin molecules. It also leads to the production of unstable beta globin molecules which cause increased destruction of red blood cell.

Alpha Thalassaemia FAQ

1How Many Types of Alpha Thalassaemia
  • Alpha Thalassaemia Silent Carrier
  • Alpha Thalassaemia Carrier
  • Haemoglobin H Disease
  • Alpha Thalassaemia Major
    • 2How can I check if I am a Carrier of Alpha Thalassaemia?
    A simple blood test can help to confirm if you carry any defective copy of the gene that causes Alpha Thalassaemia.
    3Can Alpha Thalassaemia be diagnosed before birth?
    Yes, diagnosis can be made long before the birth of the baby. This procedure is known as antenatal diagnosis. This can now be carried out as early as the 10th week of Pregnancy.
    4Who should take the Test?
  • Family History of Thalassaemia
  • IF REPRODUCTIVE PARTNER IS A KNOWN CARRIER
  • High Risks of conceiving a child with Hb H disease or the potentially devastating Hb Barts hydrops foetalis
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    Reportable

    Assay detects the common
    α+ Thalassaemia mutations

    (alpha 3.7kb and 4.2kb deletions)

    and the α0-thalassaemia mutations
    (SEA, MED1, MED2, 20.5kb, FIL, THAI, Dutch1 deletions & Hb Constant Spring)

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    METHODS

    GAP-PCR for common deletions.

    Sanger Sequencing confirmation of HbCS.

    Multiplex Ligation-dependent Probe Amplification (MLPA) as a Reflex Testing.

    HBA1 & HBA2 Gene Sequencing:
    Second-line testing for denovo and rare variants.

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