Mecasermin for the treatment of Rett Syndrome: a systematic review

Mecasermin, a recombinant analogue of insulin‑like growth factor 1 (IGF‑1), is under investigation as a potential therapy for Rett syndrome (RTT), a neurodevelopmental disorder resulting from mutations in the MECP2 gene. In this systematic review, we assessed the impact of mecasermin on the full spectrum of RTT severity by screening relevant clinical studies identified through MeSH‑based database queries. Evidence indicates that IGF‑1 administration may help preserve social engagement and cognitive function in RTT, although autonomic control and behavioral outcomes have been inconsistent, and electroencephalographic alterations display considerable heterogeneity. Moreover, transcriptomic analyses have uncovered discrete gene‑expression signatures in molecularly defined patient subgroups, suggesting that genetic background modulates therapeutic response. These findings highlight the promise of mecasermin for ameliorating specific RTT features while underscoring the necessity of larger, rigorously designed trials to refine treatment regimens and implement stratified, patient‑specific approaches.