Inheritance of chromosome heteromorphisms analyzed by high-resolution bivariate flow karyotyping

The DNA content of the mitotic chromosomes from 10 children and their parents in four families were quantified by bivariate flow karyotyping. In all cases, each chromosome peak in the flow karyotype of the child could be traced to one of the two parents. The measured absolute difference in homologue DNA content between children and their parents averaged 0.8%, or approximately 1 Mbp over all chromosome types. This study demonstrates that flow karyotypes of a proband's parents can be an aid in detecting and quantifying the size of de novo deletions that involve heteromorphic chromosome types.