Beckwith-Wiedemann Syndrome in Humans Is Characterized by "Overgrowth" in Childhood

Short Answer

Beckwith-Wiedemann syndrome in humans is characterized by "overgrowth" in childhood, sometimes leading to unusually large parts of the body. An imprinted gene cluster on chromosome 11 is associated with this disease. The cluster contains several genes including Igf2 and H19. Igf2 encodes an insulin-like growth factor that is maternally imprinted, i.e. the maternal copy is not expressed. However, the DNA methylation pattern of this locus is not different between the two homologous chromosomes. On the other hand, H19 is also imprinted and its methylation pattern does differ between the two parental chromosomes. H19 is transcribed into a noncoding RNA that appears to silence the transcription of the Igf2 gene in cis. Would you expect the H19 locus to be hypermethylated in the maternally inherited chromosome (M) or paternally inherited chromosome (P)? Write down M or P as your answer.