Genomic imprinting is seen in

Ref Robbins 9/e p172 Angelman syndrome, as might be expected, also can result from uniparental disomy of parental chromosome 15. The Angelman syndrome gene (imprinted on the paternal chro- mosome) is now known to encode a ligase that has a role in the ubiquitin-proteasome proteolytic pathway (Chapter 1). This gene, called, somewhat laboriously, UBE3A, is expressed primarily from the maternal allele in specific regions of the normal brain. In Angelman syndrome, UBE3A is not expressed in these areas of the brain--hence the neurologic manifestations. Prader-Willi syndrome, unlike Angelman syndrome, probably is caused by the loss of function of several genes located on chromosome 15 between q11 and q13. These genes are still being fully characterized.