There is no direct evidence of imprinting but melanotroph tumours of the pituitary have an earlier
onset when mutant Rb1 is paternally inherited (Harrison
DJ et al, 1995; Nikitin
AY et al, 1997).
An imprinted CpG island has been identified at the human RB1 locus, controlling expression of an
alternative imprinted RB1 transcript, that is thought to have arisen from a degraded KIAA0649
D et al, 2009). There is no evidence to suggest imprinting of Rb1 in mice (Kanber D et al, 2009).