Genotype–Computed Tomography Phenotype of the RSPH4A Founder Variant in Primary Ciliary Dyskinesia

Background/Objectives: Primary ciliary dyskinesia (PCD) caused by biallelic RSPH4A variants is enriched in the Puerto Rican population due to the founder allele c.921+3_921+6delAAGT, a 4-nucleotide deletion affecting the intron 6 splice donor. This study aimed to characterize the genotype–computed tomography (CT) phenotype associated with homozygosity for this founder variant and examine relationships among age, pulmonary function, and structural lung disease.