Male MEIKIN mutations cause sperm chromosome chaos and recurrent blastulation failure afteriIntracytoplasmic sperm injection

We describe a unique phenotype, blastulation failure, in three primary infertile males with oligoasthenoteratozoospermia (OAT) who underwent intracytoplasmic sperm injection (ICSI), resulting in multiple good-quality cleavage embryos that repeatedly failed to achieve blastulation or implantation. Single-cell analysis revealed that the arrested embryos had complex spermatozoa-derived chromosomal abnormalities, major embryonic genome activation failure, and overactivation of stress and apoptosis pathways at the transcriptional level. We further identified mutations in the meiosis-specific kinetochore factor MEIKIN gene in these males, causing OAT and chromosomal chaos in the spermatozoa. This study is the first to establish a connection between the genetic etiology of OAT and a novel embryo development arrest phenotype, indicating potenial risks of ICSI for OAT patients and providing a new explanation for recurrent implantation failure. Arrested embryos from patients with MEIKIN gene mutations were separated into single blastomeres for smart-seq2 sequencing to explore alterations in gene expression.