CTNNA3 (catenin (cadherin-associated protein), alpha 3) was reported to show polymorphic imprinting.
It showed monoallelic expression in ONE of
three placental samples (8-12 weeks gestation); the other two showed equal biallelic expression.
Immunostaining of a partial hydatidiform mole showed absence of expression in villous trophoblast of
villi with hydropic changes (the presumed androgenetic villi), whereas expression was detected in
non-hydropic villi of normal origin (van
Dijk M et al, 2004). CTNNA3 was studied since it was a candidate for the parent-of-origin effect
in familial pre-eclampsia, but subsequent studies have excluded CTNNA3 from the minimal critical
Dijk M et al, 2005).
M et al (2007) reported biallelic expression in normal urothelial samples.
In mice, allele-specific expression studies showed biallelic expression in mouse fetal and placental
I et al, 2007).
In view of negative reports, the evidence from a single sample is no longer sufficient to sustain a
claim of polymorphic imprinting (IMM - comment).