Molecular characterization of 18p deletions: evidence for a breakpoint cluster.

Abstract

To determine the size and parental origin of the deletion in individuals with 18p- syndrome. Molecular and fluorescence in situ hybridization analyses of the pericentromeric region of chromosome 18 were performed on genomic DNA and chromosomes from study participants. The majority of the breakpoints were located between markers D18S852 on 18p and D18S1149 on 18q, a distance of approximately 4 Mb. The parental origin of these deletions appears to be equally distributed, half maternally derived and half paternally derived. The distributions of both the size and parental origin of the 18p deletions support the presence of a breakpoint cluster in the 18p- syndrome.