In the leptin-hypothalamic-sympathetic nervous system (LHS) concept for AIS pathogenesis of girls, scoliosis initiation is attributed to increased hypothalamic sensitivity to leptin [for central leptin activity see [83,173,174] with sympathoactivation becoming asymmetric as an adverse hormetic effect [7,175,176]; this places AIS with lower BMI at the opposite end of the spectrum from the central leptin resistance concept for obesity [7]. Here, LEP is linked to obesity due to melanocortin 4 receptor deficiency.