A couple good articles from the Ottawa Sun give some relevant info about WS.
Patients with Williams Syndrome are often plagued with eating difficulties, with many suffering from a sensitive gag reflex and raised levels of calcium. Feeding problems are what made Racey decide to take her daughter to CHEO originally and it continues to be a main focus in Violet's treatment plan as she is now fed through a feeding tube surgically inserted into her stomach. Racey is working hard to raise awareness and share knowledge about the condition so other families can consider it when searching for their own answers. "There are many doctors out there who know nothing about Williams Syndrome," said Racey, noting her own family doctor had never heard of it.
See more at http://www.ottawasun.com/2015/07/04/williams-syndrome-affects-1-in-10000-says-cheo-doc