{Reference Type}: Journal Article {Title}: Williams syndrome. {Author}: Twite MD;Stenquist S;Ing RJ; {Journal}: Paediatr Anaesth {Volume}: 29 {Issue}: 5 {Year}: 05 2019 {Factor}: 2.129 {DOI}: 10.1111/pan.13620 {Abstract}: Williams syndrome affects approximately one in 10 000 people and is caused by the deletion of genes on chromosome 7q11.23 which code for elastin. The phenotypic appearance of people with Williams syndrome is well characterized, but there continues to be new genetic and therapeutic discoveries. Patients with Williams syndrome have increased morbidity and mortality under sedation and anesthesia, largely as a result of cardiovascular abnormalities. This review article focuses on new information about Williams syndrome and outlines a structured approach to patients with Williams syndrome in the perioperative period.