ESR1 and androgen insensitivity syndrome: ESR1 expression was significantly higher in deep paraspinal muscles compared to superficial ones and there is a left-right asymmetry of ESR1 and ESR2 expression in deep muscles (Kotwicki et al., 2022), with the authors further showing this asymmetry had a significant relationship with both the curve severity via Cobb angle and with the progression risk factor in AIS.