BCORL1, POF1B, and USP9X copy number variation in women with idiopathic diminished ovarian reserve

To analyze the copy number variation (CNV) in the X-linked genes BCORL1, POF1B, and USP9X in idiopathic diminished ovarian reserve (DOR).

This case-control study included 47 women, 26 with DOR and 21 in the control group. Age, weight, height, BMI, and FSH level were evaluated, as well as antral follicle count (AFC), oocyte retrieval after controlled ovarian stimulation, and metaphase II (MII) oocytes. The CNVs of BCORL1, USP9X, and POF1B genes were measured by quantitative real time PCR (qPCR) using two reference genes, the HPRT1 (X-linked) and MFN2 (autosomal). Protein–protein interaction network and functional enrichment analysis were performed using the STRING database.

The mean age was 36.52 ± 4.75 in DOR women and 35.38 ± 4.14 in control. Anthropometric measures did not differ between the DOR and control groups. DOR women presented higher FSH (p = 0.0025) and lower AFC (p < .0001), oocyte retrieval after COS (p = 0.0004), and MII oocytes (p < .0001) when compared to the control group. BCORL1 and POF1B did not differ in copy number between DOR and control. However, DOR women had more copies of USP9X than the control group (p = 0.028).

The increase in the number of copies of the USP9X gene may lead to overexpression in idiopathic DOR and contribute to altered folliculogenesis and oocyte retrieval.