I was reading up on KCNQ1, which encodes a voltage-gated potassium channel, and I discovered that it happens to be only maternally expressed. This is regulated by KCNQ1OT1, a non-coding RNA, which is also epigenetically regulated (expressed only paternally). Mutations in KCNQ1OT1 are associated with Beckwith-Wiedemann Syndrome (BWS).
Further reading led to the discovery that there are ART-related (assisted reproductive technology) cases of BWS due to loss of methylation at KCNQ1.
However, this article found epigenetic stability of KCNQ1OT1 methylation in cultured human embryonic stem cells, which leads me to think that KCNQ1 might also have been properly methylated.
So what exactly are assisted reproductive technologies doing that can disrupt inheritance of epigenetic marks (that culturing hESCs doesn't do)? (Is this understood for any gene?)