Cmah (cytidine monophospho-N-acetylneuraminic acid hydroxylase) is one of the ten genes reported by
Brideau et al to be imprinted and maternally expressed in the mouse placenta. No evidence of
imprinting was detected in E17.5 brain from reciprocal crosses. However, for Cmah the evidence was
more apparent for one direction of the cross than the other (Brideau
CM et al, 2010).
However, Okae H et al (2012) reported
negligible expression of Cmah by qPCR and whole transcriptome sequencing in E13.5 placentas. They
suggest that this gene is not imprinted. This is concordant with the caution from Proudhon and Bourc'his (2010) that maternal contamination of placental tissues may
cause apparent imprinted maternal expression.