First-Year Outcomes of Newborn Sickle Cell Disease Screening in an Angolan Hospital

Sickle Cell Disease (SCD) is a hereditary recessive disorder that affects over 7 million people worldwide. Although its incidence is particularly high in sub-Saharan Africa, early diagnosis is still not widely available in these countries. In Angola, it is believed that the prevalence of SCD can exceed 3%, and carriers of the S allele account for about 20% of the population. If undiagnosed, it is estimated that 50 to 90% of children die before reaching their 5th birthday. Therefore, early diagnosis is essential, and when combined with follow-up programs for SCD, mortality and morbidity rates are substantially reduced.

The main goal of the present project is to implement a newborn screening for SCD in one of the biggest maternities in Luanda (Angola), Hospital Materno Infantil Dr Manuel Pedro Azancot de Menezes, and support the pediatric follow up of the SCD children.

To guarantee this project’s success, in June 2023, and after ethical approval, the newborn screening started with the training of all the health professionals involved. All the children born (or vaccinated) at this maternity are included in the screening, after parental (or legal guardian) consent. Blood is collected by heel prick test to filter paper. Samples are then frozen and sent to Lisbon (Portugal) for hemoglobin electrophoresis by Isoelectric Focusing (IEF) in the equipment Migele (acquired with the support of Revvity and Arise project). All the samples identified as being SS, are then confirmed by PCR-RFLP. Other variable electrophoretic patterns are also being analyzed by PCR and DNA sequencing, such as mutations in alpha, gamma or beta globin Gene.

In one year (June 2023 to May 2024) 10,400 blood samples were collected, and 9,074 were analyzed by IEF. A total of 121 children (1.33% prevalence) were identified and confirmed as SS and were contacted for follow up and start prophylactic therapies. The prevalence of carriers of the S allele is 20,28% (1840). The frequency of C allele is very low (just 6 heterozygotes AC were identified). We also identified 25 children with other mutations in the β and α genes, all in heterozygosity, who are being further analyzed.

Parents of all the SS children are being contacted to start follow up consultations. However, most of the parents are refusing the first consultation claiming the absence of symptoms, and some return to the hospital after the appearance of first vaso-occlusive crises.

With the support of the “ARISE- African Research and Innovative Initiative for Sickle cell Education”, 27 laboratory technicians from Angola and Nigeria were received in Lisbon for training in the IEF technique and genetic analysis. With this training we expect that in the near future all the laboratory procedures can be performed in the Hospital main laboratory, and also that this newborn screening may be replicated in other hospitals.

At the moment, we are beginning to plan educational programs to increase consultation acceptance following positive screenings, inform parents about the importance of follow-up care, and advise them on the risk of incidence in future children.

The results of this study support the estimates of a high prevalence of SCD in Angola, showing that newborn screenings for early diagnosis of SCD are feasible, should be a prioritized and implemented at national level.

This project has the support from Revvity,(ARISE) EU Horizon 2020 Marie Skłodowska-Curie grant agreement No 824021, FCT/MCTES H&TRC UIDB/05608/2020 e UIDP/05608/2020 and IPL/IDI&CA2024/GenFalci_ESTeSL.