Koolen-de Vries syndrome in a 63-year-old woman: a review of the adult phenotype Koolen-de Vries syndrome (KdVS): An Introduction Also known as the 17q21.31 microdeletion syndrome, Koolen-de Vries syndrome (KdVS) was first described in 2006 in individuals with intellectual disabilities and organ abnormalities. KdVS was initially described in association with recurrent microdeletion