Implementation of third-generation digital PCR for non-invasive prenatal diagnosis of sickle cell disease and early detection. Pilot study

Sickle cell disease (SCD) is one of the most prevalent autosomal recessive conditions worldwide, affecting more than 600,000 newborns annually. Despite advances in treatment, it remains a chronic condition requiring lifelong management. Allogeneic transplantation and gene therapy are currently the only curative options when applicable and available. We present the results of a pilot study evaluating the use of digital PCR (dPCR) for non-invasive prenatal diagnosis (NIPD), a minimally invasive approach for SCD, based on relative pathogenic variant dosage (RMD, Relative Mutation Dosage) analysis in maternal plasma. Nine pregnant women carrying the pathogenic variant (βA/βS) were included. RMD values ranged from 0.436 to 0.501 (mean: 0.475) in cases with heterozygous fetuses and from 0.377 to 0.431 (mean: 0.397) in cases with wild-type fetuses. Z-score classification correctly identified fetal genotype in all conclusive cases (8/9), with one inconclusive result. Results were confirmed postnatally with 100% concordance in classified cases. These findings support the feasibility of dPCR-based NIPD for SCD as a minimally invasive approach. However, further validation in larger cohorts and with comprehensive quality control parameters is required.