A 5-kb imprinting center deletion in a family with Angelman syndrome reduces the shortest region of deletion overlap to 880 bp.

Imprinting on human chromosome 15q11-q13 is controlled by a bipartite imprinting center (IC) that maps to the SNRPN locus. Deletions of the IC result in an imprinting defect and Prader-Willi syndrome or Angelman syndrome (AS). We have now identified a 5-kb IC deletion in an English AS patient (AS-LO); this represents the smallest microdeletion found in AS and narrows down the shortest region of deletion overlap to 880 bp.