Deletion of the long arm of chromosome 11 [46,XX,del(11)(q24.1--qter)].

A child who presented at three months of age with pyloric stenosis and pancytopenia was found to have a partial deletion of the long arm of chromosome 11, del(11)(q24.1----qter). Only two previous cases have been described with an apparently identical chromosomal deletion, and both exhibit similar phenotypic features. Other patients with larger deletions of the distal region of the long arm of chromosome 11 show many features in common with these three cases. It is suggested that the region of the long arm of chromosome 11 from band q24.1 to qter may contain the genetic material responsible for the expression of the 11q - phenotype.