Single-cell RNA sequencing of human oocytes affected by PCOS at germinal vesicle (GV), metaphase I, and metaphase II stages demonstrates upregulated genes at the GV stage affecting mitochondrial function, such as COX6B1, COX8A, COX4l1, and NDUFB9 (118). The gene discussed is COX6B1; the disease is polycystic ovary syndrome.