IMPRINT SWITCHING ON HUMAN-CHROMOSOME-15 MAY INVOLVE ALTERNATIVE TRANSCRIPTS OF THE SNRPN GENE

Imprinting on human chromosome 15 is regulated by an imprinting centre , which has been mapped to a 100-kb region including exon 1 of SNRPN. From this region we have identified novel transcripts, which represent alternative transcripts of the SNRPN gene, The novel exons lack prote in coding potential and are expressed from the paternal chromosome onl y. We have also identified intragenic deletions and a paint mutation i n patients who have Angelman or Prader-Willi syndrome due to a parenta l imprint switch failure. This suggests that imprint switching on huma n chromosome 15 may involve alternative SNRPN transcripts.