Cystic fibrosis-causing variants in Chinese patients with congenital absence of the vas deferens: a cohort and meta-analysis

Individuals with congenital absence of the vas deferens (CAVD) may transmit cystic fibrosis (CF)-causing variants of the cystic fibrosis transmembrane conductance regulator ( CFTR ) gene to their offspring through assisted reproductive technology (ART). We aimed to delineate the spectrum and estimate the prevalence of CF-causing variants in Chinese individuals with CAVD through a cohort analysis and meta-analysis. CFTR was sequenced in 145 Chinese individuals with CAVD. CFTR variants were classified as CF-causing or non-CF-causing variants regarding clinical significance. A comprehensive genotype analysis was performed in Chinese individuals with CAVD, incorporating previous studies and our study cohort. The prevalence of CF-causing variants was estimated through meta-analysis. In our cohort, 56 different CFTR variants were identified in 108 (74.5%) patients. Twenty variants were categorized as CF-causing and were detected in 28 (19.3%) patients. A comprehensive genotype analysis of 867 patients identified 174 different CFTR variants. Sixty-four were classified as CF-causing variants, 56.3% of which had not been previously reported in Chinese patients with CF. Meta-analysis showed that 14.8% (95% confidence interval [CI]: 11.0%-18.9%) CAVD cases harbored one CF-causing variant, and 68.6% (95% CI: 65.1%-72.0%) CAVD cases carried at least one CFTR variant. Our study underscores the urgent need for extensive CFTR screening, including sequencing of whole exons and flanking regions and detection of large rearrangements and deep intronic CF-causing variants, in Chinese individuals with CAVD before undergoing ART. The established CF-causing variants spectrum may aid in the development of genetic counseling strategies and preimplantation diagnosis to prevent the birth of a child with CF.