Thalassaemia screening and confirmation of carriers in parents. (February 2017)

• Record Type: Journal Article
• Authors: Barrett, Angela N.; Saminathan, Ramasamy; Choolani, Mahesh
• Is Part Of: Best practice & research. Volume 39(2017)
• Page Start: 27
• Page End: 40
• Publication Date: 2017-02
• Subjects: carrier screening -- thalassaemia trait -- haemoglobinopathy -- red blood cell indices -- HbA2; Gynecology -- Periodicals; Obstetrics -- Periodicals; Genital Diseases, Female; Obstetrics; Gynecology; Obstetrics; Periodicals; 618.05
• DOI: 10.1016/j.bpobgyn.2016.10.015
• Languages: English
• ISSNs: 1521-6934

Abstract

Abstract : Haemoglobinopathies are among the most common inherited monogenic disorders worldwide. Thalassaemia screening for carrier status is recommended for adults of reproductive age if suspected of being at risk. Conventional laboratory methods for screening include the assessment of haematological indices, and high-performance liquid chromatography, capillary electrophoresis or isoelectric focusing to measure the levels of HbA2 and HbF, and to identify haemoglobin variants. Each screening method has its advantages and disadvantages, the main disadvantage being that none can fully resolve all variants. The complex nature of the genetics of haemoglobinopathies necessitates expertise in the interpretation of screening results to evaluate the most likely genotypes, which must then be confirmed using the DNA diagnosis. This review highlights the limits and pitfalls of each screening technique, and outlines a rational combination of different methods to overcome issues in thalassaemia carrier detection. Highlights: Measurement of RBC indices and HbA2 and HbF percentages are essential for thalassaemia screening. Co-inheritance of globin gene variants with β-thalassaemia mutations can alter levels of HbA2 . Methods currently used to measure total haemoglobin are unable to distinguish all variants fully. Selection of the best approach for a laboratory will be guided by prevalence of variants in the region. Only DNA testing methods can distinguish the true nature of the thalassaemia.