Methylation analysis of the intergenic differentially methylated region of DLK1-GTL2 in human.

Imprinting is a non-Mendelian form of inheritance where epigenetic modifications control mono-allelic expression depending on the parental origin. Methylation of CpG-dinucleotides at differentially methylated regions (DMRs) is one of the best-studied mechanisms directing expression to one specific parental allele. We studied the methylation patterns of the intergenic (IG)-DMR of DLK1 and GTL2.

Methylation analysis of KvDMR1 in human oocytes.

Recently, several reports have been published that showed a higher incidence of assisted reproductive technologies (ART) in patients with Beckwith-Wiedemann syndrome compared with the general population, and in most of these patients, aberrant methylation imprints of KvDMR1 have been found. This has led to the concern that ART might increase the incidence of imprinting syndromes such as Beckwith-Wiedemann syndrome. Not much is known on environmental or genetic factors that may interfere with the processes of imprint maintenance or resetting.

Methylation imprints of the imprint control region of the SNRPN-gene in human gametes and preimplantation embryos.

Imprinting is an epigenetic mechanism leading to mono-allelic expression of imprinted genes. In order to inherit the differential epigenetic imprints from one generation to the next, these imprints have to be erased in the primordial germ cells and re-established in a sex-specific manner during gametogenesis. The exact timing of the imprint resetting is not yet known and the use of immature gametes in assisted reproductive technologies may therefore lead to abnormal imprinting and related diseases.