In a 29‑year‑old woman undergoing IVF, doctors used triptorelin to trigger egg release, but all embryos stopped developing at the 1‑ or 2‑cell stage because she had a rare double mutation in the PADI6 gene.

<b>Background:</b> The <i>PADI6</i> gene is a component of the subcortical maternal effect complex (SCMC). Mutations in the <i>PADI6</i> gene, which was the first gene discovered to impact the activation process of the human embryonic genome, have been shown to induce early embryo arrest. <b>Case:</b> A 29-year-old lady with primary infertility underwent <i>in vitro</i> fertilization embryo transfer (IVF-ET) for tubal reasons, who had normal hormone levels and ovarian reserve. A Progestin-Primed Ovarian Stimulation (PPOS) protocol of Ovarian stimulation with IVF was performed. The total of Gonadotropin (Gn) stimulation with u-FSH was 2100 IU, which lasted for 10&#xa0;days. When three follicles measuring less than 18&#xa0;mm in diameter were seen, r-hCG 250&#xa0;ug and triptorelin acetate 0.2&#xa0;mg were injected to trigger oocyte maturation. Nineteen oocytes (including thirteen MII oocytes) were picked up 37&#xa0;h after the trigger, and seven of these were normal fertilized. Unfortunately, these many embryos were stopped at the 1- or 2-cell stage, hence this infertile patient's IVF treatment won't result in an embryo transfer. Using whole-exome sequencing, a complex heterozygous mutation in <i>PADI6</i> was discovered: c. 1247T&gt;C [p.Ile416Thr] in exon 12 of <i>PADI6</i>, and c. 2009_2010del [p.Glu670GlyfsTer48] in exon 17 of <i>PADI6</i>. <b>Conclusion:</b> We found a complex heterozygous mutation in the <i>PADI6</i> gene (c. 1247T&gt;C; c. 2009_2010del) that caused embryos were arrested at the 1- or 2- cell stage. The discovery in this patient adds to the evidence showing the PADI6 gene mutation causes early embryo arrest in humans.