A skull-fusion signal shuts off by day 7.5.

The window makes the fibroblast growth factor receptor FGFR2 a drug target with a deadline.

Two tissues, the dura mater and suture mesenchyme, communicate through this receptor and retinoic acid signaling to keep the seam open.

The findings are in mice only, and no human-equivalent timeline or drug has been proposed.

Sources: Nature