Does the LEPR rs1137101 variant increase susceptibility to HPO-axis suppression during physiologic strain?

Leptin functions as a vital metabolic gatekeeper, communicating energy availability to the hypothalamic-pituitary-ovarian (HPO) axis. Research indicates that genetic variations affecting this pathway can influence an individual’s threshold for reproductive suppression under physiological stress.

Mechanistic explanations

• Receptor Alteration: The LEPR rs1137101 (Gln223Arg) variant involves a glutamine-to-arginine substitution that induces structural changes and alters hydrogen bonding within the receptor. While it may not completely block canonical STAT3 signaling, molecular simulations suggest these conformational shifts can impair receptor kinetics and signal transduction.
• Kisspeptin/GnRH Modulation: Leptin does not signal GnRH neurons directly; instead, it acts on intermediary KNDy (kisspeptin/neurokinin B/dynorphin) neurons. Impaired leptin signaling reduces the excitatory drive of kisspeptin, which is the primary "gatekeeper" of GnRH pulsatility. Without sufficient kisspeptin stimulation, GnRH pulse frequency slows, leading to downstream HPO-axis suppression.
• Energy Sensing and Stress: In the presence of physiological strain (e.g., energy deficit or intense exercise), leptin levels naturally decline. For individuals with baseline signaling impairments—such as those linked to LEPR variants—this decline more easily crosses the threshold required to maintain the GnRH pulse generator, increasing susceptibility to functional hypothalamic amenorrhea (FHA).

Clinical and effectiveness evidence

• Association with FHA: Studies of women with FHA have identified an enriched burden of rare genetic variants in pathways regulating GnRH and leptin. This suggests that genetic vulnerability at the leptin receptor locus predisposes individuals to HPO suppression when environmental triggers are present.
• Leptin Replacement: The essentiality of this pathway is demonstrated by clinical trials where recombinant leptin (metreleptin) administration restored GnRH pulsatility and ovulation in women with exercise-induced or energy-deficient amenorrhea.

Bottom line

The claim is scientifically plausible and well-supported by mechanistic logic. The rs1137101 variant alters the leptin receptor's structure, potentially lowering the threshold at which physiological stress triggers kisspeptin/GnRH suppression and HPO-axis dysfunction.