Family studies in chromosome 22q11 deletion: further demonstration of phenotypic heterogeneity.

We describe three unrelated, Scottish infants with the velocardiofacial/DiGeorge syndrome, all of whom have deletions of chromosome 22q11. Two of the infants had inherited the deletion from their mothers; the third infant's mother had clinical features although a deletion was not demonstrable in her. One infant had craniosynostosis associated with broad thumbs which may be a separate familial trait; however, at least one other 22q11 deleted individual with craniosynostosis is known and it is possible that craniosynostosis is a rare feature of this deletion syndrome. The second infant is the third reported case with isolated hypoparathyroidism and dysmorphic features associated with the 22q11 deletion. The variable clinical phenotype of these families with 22q11 deletion is discussed and compared with other reported families.