Genetic analysis and PGT-SR outcome of a male carrier of exceptional complex chromosome rearrangement
Objective:To investigate the clinical and genetic characteristics of a male carrier of exceptional complex chromo-some rearrangement(CCR)and the outcome of preimplantation genetic testing for chromosomal structural rearrangement(PGT-SR).Methods:Using the modified high resolution G banding technique and whole-genome low-coverage sequencing(WGLCS),we analyzed the cellular karyotype and molecular karyotype of a male carrier of CCR,performed an analysis of the single-sperm chromosome copy number and conducted PGT-SR for the patient by next-generation sequencing(NGS).In addition,we reviewed the literature on repor-ted male carriers of CCRs and summarized their normal/balanced sperm ratios and PGT-SR outcomes.Results:The karyotype of the patient was 46,XY,der(5)inv(5)(q14.3q23.2)t(5;14;11)(q23.2;q31.1;q21),der(11)t(5;14;11);der(14)t(5;14;11),with the translocation breakpoints located in the intergenic region.Single-sperm sequencing revealed 20.0%(7/35)of normal haploids in the male's spermatozoa,and the results PGT-SR showed a proportion of 25.0%(4/16)of normal/balanced embryos.After thawing and transferring of 2 euploid blastocysts,a healthy male infant was successfully delivered.Conclusion:The proportion of normal hap-loids in the spermatozoa of male CCR carriers may be higher than theoretically predicted,and PGT-SR can effectively improve the preg-nancy outcome in male CCR carriers and provide valuable data for genetic counseling.