Unbalanced 13;18 translocation and Williams syndrome.

A 2 1/2 year old girl is reported with a de novo 13;18 unbalanced translocation and the facial features of Williams syndrome, subaortic stenosis, failure to thrive, and developmental delay. This case provides two candidate locations for the underlying molecular pathology of this sporadic syndrome. Williams syndrome is associated with intellectual and growth retardation, infantile feeding problems which may be associated with hypercalcaemia, cardiovascular abnormalities, a friendly, loquacious personality, and a typical facies. The cause is not known and only a few chromosome abnormalities have been reported in patients with the Williams syndrome phenotype. Many papers fail to mention chromosome studies. We report a girl with an unbalanced 13;18 translocation and the Williams syndrome phenotype.