May 2024
Ampath | ampath.co.za
Overview
Haemoglobinopathies are a diverse group of inherited disorders caused by defects in either the alpha globin (HBA) or beta globin (HBB) genes.
Why consider genetic testing?
- Provides diagnostic confirmation
- Helps determine or exclude carrier status
- Enables prenatal diagnosis where parental carrier status is known
- Essential in heavily transfused individuals where a definitive diagnosis is unclear
Although not typically the first-line investigation, DNA-based testing is becoming a standard second-tier test for accurate diagnosis and family risk assessment.
Genetic Tests Available at Ampath
Ampath now offers genetic testing for:
✅ Alpha Thalassaemia
- Mnemonic:
HBAMLPA - Indications: Diagnostic confirmation, carrier screening, prenatal testing
- Specimen: 5 mL EDTA blood
- Method: Copy number detection using MLPA (Multiplex Ligation-dependent Probe Amplification)
- Turnaround time: ~4 weeks
- Genetic counselling: Pre- and post-test support available
✅ Beta Thalassaemia
- Mnemonic:
HBBSEQ - Indications: Diagnostic confirmation, carrier screening, prenatal testing
- Specimen: 5 mL EDTA blood
- Method:
- Sanger sequencing
- Copy number detection by MLPA
- Turnaround time: ~6 weeks
- Genetic counselling: Pre- and post-test support available
✅ Sickle Cell Disease
- Mnemonic:
HBSNGS - Indications: Diagnostic confirmation, carrier screening, prenatal testing
- Specimen: 5 mL EDTA blood
- Method: Sanger sequencing
- Turnaround time: ~4 weeks
- Genetic counselling: Pre- and post-test support available
Important Notes for Prenatal Testing
- Pre-test counselling is mandatory
- Prenatal testing is only offered if the familial variant(s) are known
- Notify the lab in advance before sending:
- Chorionic villus sampling (CVS)
- Amniotic fluid samples
Supporting Information for Accurate Interpretation
To enhance interpretation of genetic results, provide the following where possible:
- Detailed family history, including ancestry
- Full blood count
- Iron studies
- Protein-based testing such as:
- High-performance liquid chromatography (HPLC)
- Haemoglobin electrophoresis
📞 For pricing, counselling, or queries:
Ampath Genetics Laboratory
Tel: 012 678 0645
Email: geneticsclinic@ampath.co.za
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