HTR2A (5-hydroxytryptamine (serotonin) receptor type 2A) was expressed exclusively from maternal
alleles, that is, in fibroblasts of retinoblastoma patients with germ line deletions or
translocations it was only expressed in those with a paternally derived deletion or translocation
(5/5), but not in those with a maternal deletion (2/2). Promoter region methylation (partial)
corresponded positively with expression (Kato
MV et al 1996).
Imprinting of HTR2A may be polymorphic: in 4/18 human adult brain samples, HTR2A expression was
monoallelic whereas in 14/18 it was biallelic (Bunzel
R et al, 1998). Htr2a is imprinted in mouse (see mouse 14).
HS et al, 2004 found mono-allelic expression in liver whereas
et al, 2004 found extreme allelic imbalances for HTR2A, but the inheritance pattern was
inconsistent with genomic imprinting and they hypothesised that it may be due to random monoallelic
expression. Fukuda Y et al, 2006 also found
or allelic imbalance of HTR2A in brain and peripheral blood lymphocytes and family studies excluded
No association between HTR2A T102C with either schizophrenia or bipolar disorder was found under the
assumption of a parent of origin effect (de
Luca V et al, 2007).
Morcos L et al, (2011) found no evidence of
allelic expression bias in lymphoblast and fibroblast cell lines.