Introduction: Sickle cell disease (SCD) is a genetically inherited, recessive mutation of the haemoglobin ?S-gene. Each year, over 300,000 babies are born with SCD, which will have a significant impact on their quality of life and average life expectancy. Currently, for SCD to be tested prenatally, foetal DNA is extracted by amniocentesis, chorionic villus sampling or cordocentesis, and then analysed by polymerase chain reaction (PCR), for instance. These procedures increase the risk of foetal miscarriage by less than 0.5%. SCD may, however, be tested non-invasively using cell-free foetal DNA (cffDNA), which is extracted from maternal blood plasma. In this study, the current accuracy of using cffDNA testing for non-invasive prenatal diagnosis (NIPD) of SCD will be shown.
Methods: Using databases such as PubMed, Web of Science and Scopus, this study systematically reviewed existing studies pertaining to the use of cffDNA maternal blood samples for non-invasive prenatal testing (NIPT) or diagnosis (NIPD) for SCD in patients who were at risk of having a baby with SCD. The data collected from the systematic review of the studies was statistically analysed in the form of a meta-analysis, describing the proportion of correct diagnosis results for this method of prenatal testing.
Results: Of over 3,600 papers identified from the database searches, only five studies contained data pertaining to the use of cffDNA for prenatal testing of SCD and conformed to the inclusion criteria set out by this study. Collectively, these data showed an average of 81.30% accuracy of diagnosis when using cffDNA to test for SCD, with 18.70% of foetuses incorrectly diagnosed. These data were compiled as a Forest Plot meta-analysis.
Conclusion: CffDNA for non-invasive prenatal SCD diagnosis appears to have the potential to be an accurate technique for the testing of this genetic disease, despite not currently indicating a proportion of correct diagnosis results which would encourage the technique for clinical implementation. Whilst there are currently very limited data on the use of this technique for the specific testing of SCD, there is great opportunity for further research into the standardisation and clinical application of this procedure
