KCNK9 (potassium channel, subfamily K, member 9) is expressed predominantly in the brain. It
showed strict or predominant monoallelic expression in 7 heterozygous human fetal brain samples.
Maternal expression could be demonstrated in two cases (Ruf D et al, 2007).
PP et al (2007) found exclusive maternal expression in 9 fetal brains (gestation 63-98 d).
O et al. (2008) described a kindred with maternally inherited mental retardation dysmorphism
syndrome (Birk Barel sundrome) caused by a mutation in KCNK9.
In mouse, Kcnk9 is
about 260 kb downstream of Peg13 which has a germline maternally-methylated DMR. However, in
humans a Peg13 orthologue has not been identified and no DMRs were identified by Ruf et al.
Morcos L et al, (2011) found no evidence of
allelic expression bias in lymphoblast and fibroblast cell lines.