<unk>  (also<unk> -Beuren syndrome) is a rare genetic disorder characterized by a distinctive, "elfin" facial appearance, along with a low nasal bridge; an unusually cheerful demeanor and ease with strangers, coupled with unpredictably occurring negative outbursts; mental retardation coupled with unusual (for persons who are diagnosed as mentally retarded)  language skills; a love for music; and cardiovascular problems, such as supravalvular aortic stenosis and transient hypercalcemia.
Williams syndrome
Wolfram syndrome
Loken Senior syndrome
Williams-Campbell syndrome
Down syndrome
Lennox-Gastaut syndrome
Rotor syndrome
Goldstein-Hutt syndrome