Beta Thalassaemia
Description:
Beta thalassaemia is characterised by a reduction (β+) or absent (β0) production of the beta chains of the haemoglobin tetramer. This results in an imbalance of the alpha:beta chain ratio, resulting in excess alpha chains that cause haemolysis.
The underlying cause of beta thalassemia are mutations which have a detrimental effect on the function of the beta globin gene product. The majority of these mutations are single nucleotide substitutions which can be detected by beta globin gene sequencing. Individuals that have thalassaemic indices and a raised HbA2 but no mutations are identified after beta globin gene sequencing go on to have beta Multiplex Ligation-dependent Probe Amplification (MLPA) to detect deletions. Therefore the investigation into beta thalassaemia is a simple two-stage algorithm.
Carriers of beta thalassaemia have one normal beta globin gene and one with a beta thalassaemia mutation. The phenotypic indices show an elevated red blood cell count, the MCV is lowered to 60-75fl, the MCH is reduced to 20-25pg and the Hb A2 concentration is increased to 3.5 - 7.0%. Individuals with two defective beta globin genes are often blood transfusion dependent (beta thalassaemia major). The severity of the disease is related to the type of mutations carried. Identification of the beta thalassaemia mutations is by beta globin gene sequencing or by direct mutation analysis if the mutation is known.
The underlying cause of beta thalassemia are mutations which have a detrimental effect on the function of the beta globin gene product. The majority of these mutations are single nucleotide substitutions which can be detected by beta globin gene sequencing. Individuals that have thalassaemic indices and a raised HbA2 but no mutations are identified after beta globin gene sequencing go on to have beta Multiplex Ligation-dependent Probe Amplification (MLPA) to detect deletions. Therefore the investigation into beta thalassaemia is a simple two-stage algorithm.
Carriers of beta thalassaemia have one normal beta globin gene and one with a beta thalassaemia mutation. The phenotypic indices show an elevated red blood cell count, the MCV is lowered to 60-75fl, the MCH is reduced to 20-25pg and the Hb A2 concentration is increased to 3.5 - 7.0%. Individuals with two defective beta globin genes are often blood transfusion dependent (beta thalassaemia major). The severity of the disease is related to the type of mutations carried. Identification of the beta thalassaemia mutations is by beta globin gene sequencing or by direct mutation analysis if the mutation is known.
Clinical details:
Please state if a pregnancy is involved as antenatal work is prioritised.
Please identify partner in referral if a fetal risk assessment is required.
Please provide full blood count (FBC) and HPLC screening results and iron levels as they become available.
Please identify partner in referral if a fetal risk assessment is required.
Please provide full blood count (FBC) and HPLC screening results and iron levels as they become available.
Department:
Location:
Sample type and Volume required:
Volume of blood anticoagulated with EDTA: Adult (16 years and above) 2 x 4 ml, Children (2-15 years) 1 or 2 x 4 ml Infants (0-2 years) 1 ml.
Clotted samples are unsuitable for DNA analysis.
Blood Samples in in correct anticoagulant tubes may be rejected.
We accept DNA samples. Please provide at least 1-5µg of purified DNA
For prenatal diagnosis please refer to section for sample requirements.
Clotted samples are unsuitable for DNA analysis.
Blood Samples in in correct anticoagulant tubes may be rejected.
We accept DNA samples. Please provide at least 1-5µg of purified DNA
For prenatal diagnosis please refer to section for sample requirements.
Turnaround time:
20 working days from sample receipt. For complex cases where additional tests are required each test will add 10 working days.
In antenatal patients 10 working days from sample receipt.
Please note any clinical urgency on the referral form, so samples can be prioritised.
Special sample instructions:
Samples must be clearly labelled with the patients first name, surname, D.O.B, hospital number and the date the sample was taken. The details on the sample must correspond to the request form. Unlabelled samples will not be accepted.
Storage and transport:
Blood should be stored at 4°C where possible. Send at room temperature by first class post. If possible, please complete the request form attached and send as a hard copy (do not send electronically) with the sample. This will ensure all relevant information is available and will aid us in processing your test.
Cost:
Please contact Business Development for pricing enquiries
Contacts:
Red Cell Centre - Molecular Diagnostics Laboratory
020 3299 1246 / 2265
kch-tr.pnd@nhs.net
c/o Central Specimen Reception
Blood Sciences Laboratory
Ground Floor Bessemer Wing
King’s College Hospital
Denmark Hill
London SE5 9RS
Mon-Fri, 9.00am-5.30pm
Blood Sciences Laboratory
Ground Floor Bessemer Wing
King’s College Hospital
Denmark Hill
London SE5 9RS
Mon-Fri, 9.00am-5.30pm
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Last updated: 29/09/2022
