[Sickle cell disease in French Guiana: assessing 30 years of neonatal screening (1992-2021)]

Abstract

Background: Sickle cell disease is one of the most common genetic diseases in France. In French Guiana, neonatal screening was introduced in 1992, at the same time as other screening programs for childhood diseases. The aim of this study is to describe the organization of newborn screening for sickle cell disease in French Guiana.

Materials and methods: We used several data sources: data collected from hospital records since 2005, activity reports from the national neonatal screening program and data from screening campaigns organized by the Drepaguyane association between 2010 and 2021 on 1,300 subjects. Blood samples from newborns are collected by capillary or venous sampling and absorbed on blotting paper (Guthrie) at the same time as those for other neonatal screenings. The dried papers are sent to the inter-regional laboratory in Lille, for further processing. In Saint-Laurent-du-Maroni, in order to reduce the proportion of people lost to follow-up, a double screening is carried out and the results are returned before discharge from the maternity hospital. All data were entered into an anonymous Excel file. The data were analyzed using STATA software.

Results: Among the 175,593 screened neonates between 1992 and 2021, screening detected 823 infants with sickle cell disease and 17,950 heterozygotes. Sickle cell genotypes include 493 SS (60%), 302 SC (37%) and 28 S-Beta-thalassemia (3%). The incidence of sickle cell disease was 1/213, 95% CI [1/236-1/204], and that of heterozygotes 1/10, IC 95% [1/12-1/8]. The majority of these children (52%) were from the Maroni region. The delay between screening and test results was 7 days. Only pathological results (homozygous, heterozygous) were communicated to parents and/or the attending physician by post. These data confirm the upward trend in the number of children screened for sickle cell disease in French Guiana. Data from screening campaigns organized by the Drepaguyane association have enabled to describe the distribution of the various abnormal hemoglobin fractions, and to confirm that HbS is more frequent in Western French Guiana. In Cayenne, in 2021, the active file comprised 699 patients, including 266 children under 18 years old.

Discussion and conclusion: This study provides valuable data on 30 years of neonatal screening for sickle cell disease in French Guiana, and on the evolution of sickle cell disease patients. It confirms that French Guiana is the French territory with the highest incidence of sickle cell disease. This incidence continues to rise over time. The study reveals the improvement in the organization of sickle cell disease management in French Guiana between 1992, when screening was introduced, and the present day. It highlights the role of patient associations in the fight against this disease, by organizing awareness and screening campaigns. These data will be used to guide public health policies in the pursuit of improved care and primary prevention.

Keywords: French Guiana; Incidence; Neonatal screening; Sickle cell disease; South America.

Figure 1

Prélèvement sur papier buvard pour le test de Guthrie Sampling on blotting paper for Guthrie test

Figure 2

Techniques d’électrophorèse de l'hémoglobine Hemoglobin electrophoresis techniques

Figure 3

Évolution annuelle des grossesses en Guyane Annual evolution of pregnancies in French Guiana

Figure 4

Évolution annuelle du nombre de naissances avec syndromes drépanocytaires majeurs en Guyane Annual trend in number of births with major sickle syndromes in French Guiana

Figure 5

Répartition de l'allèle BS en Guyane (% et intervalle de confiance à 95 %) à partir du dépistage anonyme et volontaire de 1 300 sujets Distribution of the BS allele in French Guiana (% and 95% confidence interval) from anonymous and voluntary screening of 1,300 individuals