PMS2-related genes flank the rearrangement breakpoints associated with Williams syndrome and other diseases on human chromosome 7.

The human PMS2 mismatch repair gene and a family of at least 17 other related genes (named human PMSR or PMS2L genes) have been localized to human chromosome 7. Human PMS2 has been mapped previously to 7p22 and shown to be causative in hereditary nonpolyposis colon cancer (HNPCC), but the human PMS2L genes have not been positioned in the context of the physical or genetic map of chromosome 7. In this study we have used various mapping methodologies to determine the precise location of the human PMS2L genes at 7q11.22, 7q11.23, and 7q22. Within 7q11.23, human PMS2L genes were found to be present at at least three sites as part of duplicated genomic segments that flank the most common rearrangement breakpoints in Williams syndrome.