Recurrent spontaneous oocyte activation causes female infertility

• Published in: Journal of assisted reproduction and genetics Vol. 39; no. 3; pp. 675 - 680
• Main Authors: Coskun, Serdar, Maddirevula, Sateesh, Awartani, Khalid, Aldeery, Meshael, Qubbaj, Wafa, Kashir, Junaid, Alkuraya, Fowzan S.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-03-2022; Springer Nature B.V
• Subjects: Calcium signalling; Embryo transfer; Embryo Transfer - methods; Embryogenesis; Etiology; Female; Gamete Biology; Gynecology; Human Genetics; Humans; Infertility; Infertility - therapy; Infertility, Female - genetics; Infertility, Female - pathology; Investigations; Medicine; Medicine & Public Health; Molecular modelling; Oocyte Retrieval; Oocytes; Oocytes - physiology; Patients; Pregnancy; Pronucleus; Reproductive Medicine; Sperm; Sperm Injections, Intracytoplasmic - methods; Paternal contribution; Spontaneous oocyte activation; Recurrent pregnancy loss; Unexplained infertility; Genetic analysis
• ISSN: 1058-0468; 1573-7330
• DOI: 10.1007/s10815-022-02435-x

Purpose
Spontaneous oocyte activation (SOA) is a recently classified phenomenon characterized by the presence of a single pronucleus immediately following oocyte retrieval, without the apparent involvement of sperm. SOA currently remains poorly understood in humans, with no clear genetic or pathological factor(s). Herein, we report two separate cases of recurrent spontaneous oocyte activation, investigating potential avenues to identify causative etiology.
Methods
Two patients with several cycles with SOA have undergone further genetic and embryologic investigation to reveal underlying causes for SOA and provide a treatment if possible.
Results
One case was a patient with recurrent pregnancy loss and the other was diagnosed as unexplained infertility. In the first case, 61 out of 69 oocytes retrieved exhibited SOA in five cycles while in the second case 44 out of 49 oocytes exhibited SOA in five cycles. Oocytes were injected with sperm; embryo development and presence of paternal contribution were investigated. No pregnancy is ensued following embryo transfer in both patients. Time-lapse imaging of embryogenesis from the second case did not reveal even momentary second pronucleus appearance. We also performed clinical whole exome sequencing for both patients but did not identify any disease-causing variant.
Conclusion
Patients with SOA suffer from infertility. Our results indicate that more investigation is required to understand the etiology of SOA in humans concentrating on the molecular mechanisms that underpin regulation of oocyte activation and calcium dynamics need to be investigated to fully understand, and perhaps in the future rectify, recurrent SOA.