Prevalence of sickle cell disease and sickle cell trait in national neonatal screening studies

Abstract

Sickle cell anemia is the best known hereditary blood disorder; there are serious complications associated with the condition. Diagnosis and early intervention reduce morbidity and mortality. These benefits have resulted in the widespread use of newborn screening education programs. In Brazil, the National Neonatal Screening Program established by decree 822/01 included sickle cell disease in the list of diseases tested in the so called "heel prick test". Since then, national studies of the results of this program have been periodically published. To review the literature in order to assess the prevalence of sickle cell trait and sickle cell anemia from data of national neonatal screening studies on hemoglobin S (Hb S). A bibliographic review was carried out using the key words: sickle cell anemia & hemoglobinopathies & neonatal screening & Brazil in the Bireme and SciELO databases. Original Brazilian studies presenting data on prevalence of the sickle cell trait (Hb AS) and sickle cell anemia (Hb SS) based on neonatal screening for Hb S were analysed. Twelve original national studies were identified with prevalences varying from 1.1% to 9.8% for the sickle cell trait and from 0.8 to 60 per 100,000 live births for sickle cell disease in different Brazilian regions. Conclusion: Neonatal screening for Hb S is a very useful method to assess the prevalence of sickle cell trait (Hb AS) and sickle cell anemia (Hb SS) in Brazil. There is a heterogeneous distribution of this disease with the highest prevalence in the northeastern region and the lowest prevalence in the south.

Congolese children with sickle cell trait may exhibit glomerular hyperfiltration: A case control study

“…Different migrations have promoted the expansion of the gene in other parts of the world . In United States, the sickle cell trait varies from 7% to 10% among African descendants . The higher concentration of this sickle cell trait is found in Africa, in the Mediterranean region and the Middle West .…”

Prevalence of Hb S (HHB: c.20A > T) in a Honduran Population of African Descent

“…The largest number of publications concerning the prevalence of this genetic condition in Latin America comes from Brazil (21,22). For this country, Lervolino et al (23) reported a national prevalence of 9.8% for the carrier genotype; they also reported that there were between 0.8 to 60 cases of newborns with sickle cell disease for every 100,000 live births/year heterogeneously distributed in this population.…”

Sickle Cell Trait: A Benign State?

“…Review of data from two decades of newborn screening in the United States revealed a prevalence of 1.5% [15] , but the prevalence in African Americans is about 8% [16] , which is similar to that of other African populations who migrated out of Africa as a result of the slave trade. As in African Americans, the prevalence in Brazil and Jamaica is about 10% [17,18] . The rising prevalence of the traits in other western populations is now of concern and public health significance.…”