SPP1 and congenital bilateral aplasia of vas deferens from CFTR mutation: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to further verify the hub genes (SPP1, HMOX1 and CD28), miRNAs (hsa-miR-525-5p and hsa-miR-6809-3p) and the top differentially expressed circRNAs (hsa-circ-0073813, hsa-circ-0073816, hsa-circ-0027587 and hsa-circ-0073645) in the ceRNA network from clinical CAVD and non-calcific valve samples.