Tel Aviv University scientists have linked gene Gtf2i to Williams Syndrome (WS) and the thinning of the myelin layer that protects neurons in the brain. In lab tests they managed to reverse some WS symptoms using the FDA-approved antihistamine clemastine fumarate.
https://socsci3.tau.ac.il/boazbarak/research/
http://news.mit.edu/2019/neuroscientists-reverse-symptoms-williams-syndrome-0422