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Molecular characterisation of 36 multilocus imprinting disturbance (MLID) patients: a comprehensive approach.

Published version
Peer-reviewed

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Authors

Bilo, Larissa 
Ochoa, Eguzkine 
Lee, Sunwoo 
Dey, Daniela 
Kurth, Ingo 

Abstract

BACKGROUND: Imprinting disorders (ImpDis) comprise diseases which are caused by aberrant regulation of monoallelically and parent-of-origin-dependent expressed genes. A characteristic molecular change in ImpDis patients is aberrant methylation signatures at disease-specific loci, without an obvious DNA change at the specific differentially methylated region (DMR). However, there is a growing number of reports on multilocus imprinting disturbances (MLIDs), i.e. aberrant methylation at different DMRs in the same patient. These MLIDs account for a significant number of patients with specific ImpDis, and several reports indicate a central role of pathogenic maternal effect variants in their aetiology by affecting the maturation of the oocyte and the early embryo. Though several studies on the prevalence and the molecular causes of MLID have been conducted, homogeneous datasets comprising both genomic and methylation data are still lacking. RESULTS: Based on a cohort of 36 MLID patients, we here present both methylation data obtained from next-generation sequencing (NGS, ImprintSeq) approaches and whole-exome sequencing (WES). The compilation of methylation data did not reveal a disease-specific MLID episignature, and a predisposition for the phenotypic modification was not obvious as well. In fact, this lack of epigenotype-phenotype correlation might be related to the mosaic distribution of imprinting defects and their functional relevance in specific tissues. CONCLUSIONS: Due to the higher sensitivity of NGS-based approaches, we suggest that ImprintSeq might be offered at reference centres in case of ImpDis patients with unusual phenotypes but MLID negative by conventional tests. By WES, additional MLID causes than the already known maternal effect variants could not be identified, neither in the patients nor in the maternal exomes. In cases with negative WES results, it is currently unclear to what extent either environmental factors or undetected genetic variants contribute to MLID.

Description

Acknowledgements: We thank the patients and their families for participation.

Keywords

Beckwith–Wiedemann syndrome, ImprintSeq, MS-MLPA, Maternal effect variants, Multilocus imprinting disturbances, Silver–Russell syndrome, Whole-exome sequencing, DNA Methylation, Genomics, Genotype, High-Throughput Nucleotide Sequencing

Journal Title

Clin Epigenetics

Conference Name

Journal ISSN

1868-7075
1868-7083

Volume Title

Publisher

Springer Science and Business Media LLC
Sponsorship
Deutsche Forschungsgemeinschaft (EG113/15–1, EG113/15–1, EG113/15–1, EG113/15–1, EG113/15–1, EG113/15–1, EG113/15–1)
NIHR Cambridge Biomedical Research Centre (BRC-1215-20014, BRC-1215-20014, BRC-1215-20014, BRC-1215-20014, BRC-1215-20014, BRC-1215-20014, BRC-1215-20014)