Abstract Rationale Primary Ciliary Dyskinesia (PCD) is a rare, genetically heterogeneous disorder caused by defects in motile cilia that impair mucociliary clearance and lead to chronic respiratory disease. In Puerto Rico, the RSPH4A c. 921 + 3₆delAAGT founder genetic variant accounts for nearly 70% of confirmed PCD cases, reflecting a strong regional founder effect. In 2024, the CILIA4PR Research Team initiated pilot molecular testing for this genetic variant using specimens from the island’s Newborn Screening Program. This initiative provided a unique opportunity to compare the geographic distribution of RSPH4A carriers detected at birth with the localization of clinically diagnosed PCD cases and to identify regional hot spots with increased carrier prevalence. Methods Data from 26 newborns identified through the Newborn Screening Program (25 heterozygous carriers and 1 homozygous) and 36 clinically confirmed RSPH4A-PCD patients were analyzed by municipality. Geographic mapping was performed using Datawrapper to visualize carrier density and patient localization. Statistical analyses included Spearman’s rank correlation to assess the relationship between newborn carriers and PCD cases, complemented by qualitative identification of regional clustering patterns consistent with genetic hot spots. Results Geographic correlation analysis demonstrated a significant relationship between the distribution of newborn carriers and clinically confirmed PCD cases associated with the RSPH4A founder genetic variant. Spearman’s rank correlation showed a moderate but statistically significant positive association (ρ = 0. 52, p = 0. 012) between the number of newborns identified through screening and the number of PCD patients by municipality. Regions with higher carrier detection rates, particularly in Bayamón, Corozal, Orocovis, and Arecibo, emerged as geographic hot spots for increased carrier risk and exhibited higher concentrations of confirmed RSPH4A-PCD cases. This concordance supports the persistence of the founder variant in northern and central municipalities and highlights the presence of stable regional hot spots of genetic risk in Puerto Rico. Conclusions The overlap between newborn screening data and clinical PCD cases reveals a distinct geographic signature and identifies regional hot spots of increased carrier prevalence. Integrating genetic screening with clinical surveillance enhances early detection, informs targeted counseling, and supports regional public health strategies for rare respiratory diseases in founder populations. This abstract is funded by: Cilia4PR Lab, Immunology and Molecular Pathogenesis Laboratory, Ponce Research Institute
Soto et al. (Fri,) studied this question.