Counsel a family on a new Williams syndrome diagnosis and anaesthetic safety — OSCE

The parents of an eight-month-old girl have just received a confirmed Williams syndrome diagnosis (7q11.23 microdeletion on chromosomal microarray) after she presented with failure to thrive, irritability, a murmur, and an elevated serum calcium. Echocardiography shows supravalvular aortic stenosis with a moderate gradient. The parents are relieved to have an explanation for her difficulties but anxious because a relative told them Williams syndrome causes sudden death. They have also been told by their dentist that her dental work can be done under sedation in a community clinic, and they want to proceed quickly. They are charmed by her sociable, smiling manner and believe she is brighter than other babies her age. Counsel them.