Chromosomal scan of single sperm cells by combining fluorescence-activated cell sorting and next-generation sequencing

Purpose The purpose of this study was to develop a feasible approach for single sperm isolation and chromosome analysis by next-generation sequencing (NGS). Methods Single sperm cells were isolated from semen samples of normozoospermic male and an infertile reciprocal translocation (RcT) carrier with the 46,XY,t(7;13)(p12;q12.1) karyotype using the optimized fluorescence-activated cell sorting (FACS) technique. Genome profiling was performed using NGS. Results Following whole-genome amplification, NGS, and quality control, the final chromosome analysis was performed on 31 and 6 single cell samples derived from the RcT carrier and normozoospermic male, respectively. All sperm cells from normozoospermic male showed a normal haploid 23-chromosome profile. For the RcT carrier, the sequencing data revealed that 64.5% of sperm cells harbored different variants of chromosome aberrations, involving deletion of 7p or 7q, duplication of 7p, and duplication of 13q, which is concordant with the expected chromosome segregation patterns observed in balanced translocation carriers. In one sample, a duplication of 9q was also detected. Conclusions We optimized FACS protocol for simple and efficient isolation of single human sperm cells that subsequently enabled a successful genome-wide chromosome profiling and identification of segmental aneuploidies from these individual cells, following NGS analysis. This approach may be useful for analyzing semen samples of infertile men or chromosomal aberration carriers to facilitate the reproductive risk assessment.