Two novel PLCZ1 frameshift mutations caused near-total IVF failure; adding assisted oocyte activation pushed fertilization rates to 73–80%
Journal: Molecular Genetics & Genomic Medicine | Published: 2026-06 | Type: Case Series + Literature Review | PMID: 42298771 Authors: Yang Jinwei et al. — Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China Funding/COI: Key Research and Development Program of Gansu Province; Natural Science Foundation of Gansu Province; Science and Technology Program of Gansu Province. No COI declared.
Two men with unexplained fertilization failure after intracytoplasmic sperm injection (ICSI) were found by whole-exome sequencing to carry novel homozygous frameshift mutations in PLCZ1, a gene encoding the sperm-borne phospholipase that triggers calcium oscillations at fertilization. Nearly all embryos failed to fertilize in the first ICSI cycle. When assisted oocyte activation (AOA) was added to the second cycle, fertilization rates rose to 72.7% and 80.0%, and both couples delivered healthy children. A concurrent literature review synthesized 24 published studies covering 77 patients and 46 distinct PLCZ1 variants.
This is a two-patient case series — the smallest unit of clinical evidence. The genetic methodology is sound: whole-exome sequencing followed by Sanger sequencing validation and bioinformatics pathogenicity scoring using ACMG criteria. For Family 1, parental carrier status was confirmed, establishing the expected autosomal recessive inheritance pattern. That's the most you can ask from a case report.
The attached literature review adds useful epidemiological texture — 24 studies and 77 patients across multiple databases (PubMed, CNKI, Wanfang) — but pooling heterogeneous case reports and case series into aggregate mutation frequencies is descriptive work, not meta-analysis. No statistical synthesis, no quality scoring of included studies. It maps the mutational landscape without quantifying uncertainty.
This paper does exactly what a well-executed case report should do: identify a novel genetic cause, document the intervention that worked, and contextualize findings against the existing literature. The science is careful within its constraints. But two patients and no controls means this contributes zero generalizable efficacy data — AOA may have helped, or the second cycle may simply have performed better for unrelated reasons. The clinical takeaway — that PLCZ1 sequencing should be considered in unexplained ICSI failure — is reasonable and consistent with the broader literature, though this paper alone cannot prove it. Worth reading if you're tracking PLCZ1 mutations; not worth citing if you need evidence for clinical decision-making.