Identification of a novel ESR1 mutation in a Chinese PCOS woman with estrogen insensitivity in IVF treatment.

Background: Polycystic ovary syndrome (PCOS) is a complex reproductive disorder, that affects approximately 5-10% of women of reproductive age. The disease is complex because its evolution may be impacted by genetic, lifestyle and environmental factors. Previous studies have emphasized the important roles of estrogen receptors in the pathogenesis of PCOS.

Objective: To use whole exome sequencing (WES) to assess possible pathogenic factors in a PCOS patient who exhibited estrogen insensitivity during hormone replacement therapy (HRT) treatment.

Methods: Genome sequencing and variant filtering via WES were performed in a patient with PCOS. DNA extraction from 364 unrelated female controls without PCOS was followed by PCR amplification, Sanger sequencing and sequence alignment. Evolutionary conservation analysis, protein structural modelling and in silico prediction were applied to analyse the potential pathogenicity of the novel ESR1 mutation.

Result(s): During the controlled ovarian hyperstimulation (COH) period of an IVF cycle, the patient experienced markedly prolonged ovarian stimulation due to a poor response to gonadotropins (Gn) and elevated serum FSH. A novel heterozygous ESR1 mutation, c.619G > A/p.A207T, leading to the replacement of a highly conserved alanine with a threonine, was identified in this patient, via WES analysis. This novel variant was not identified in 364 unrelated female controls without PCOS, or in the Exome Aggregation Consortium (ExAC) or 1000 Genome Project.

Conclusion(s): We identified a novel heterozygous ESR1 mutation in a Han Chinese PCOS woman exhibiting clinical signs of estrogen insensitivity. This study may provide new strategies for IVF therapy, especially for patients who exhibit estrogen insensitivity during IVF cycle.