Williams-Beuren syndrome (WBS) is a rare, untreatable genetic disease caused by a submicroscopic hemizygous deletion in chromosome 7, which is estimated to affect 1/7500-10 000 newborns. 1 A region of 26-28 genes is involved, including the Elastin gene. This genetic abnormality is linked to cardiovascular, neurocognitive and endocrine disorders, as well as to orbital, musculoskeletal, gastrointestinal and urogenital affectations. 1 50% of individuals with WBS present hypertension, 1 supravalvular aortic stenosis and segmental narrowing of arteries. They have an increased risk of diabetes mellitus and impaired glucose tolerance. 31.5% of WBS patients are reported to have subclinical hypothyroidism 5 and 5%-50% of WBS children present hypercalcaemia. 1 A different proportion of the grey and white matter has been suggested to be the reason for their specific behavioural and cognitive profile. 2 Individuals with