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Pediatr Blood Cancer. 2017 Mar;64(3). doi: 10.1002/pbc.26241. Epub 2016 Sep 21.

Novel deletion in 11p15.5 imprinting center region 1 in a patient with Beckwith-Wiedemann syndrome provides insight into distal enhancer regulation and tumorigenesis.

Author information

1
Center for Human Genetics, Bioscientia, Ingelheim, Germany.
2
Department for Pediatrics, Medical University Innsbruck, Innsbruck, Austria.
3
Tyrolean Cancer Research Institute, Innsbruck, Austria.
4
Center for Pediatrics and Adolescent Medicine, Johannes Gutenberg University Medical Center, Mainz, Germany.
5
Division of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria.
6
Department of Medicine, University Hospital Freiburg, Freiburg, Germany.

Abstract

BACKGROUND:

Beckwith-Wiedemann syndrome (BWS) is an early-onset overgrowth disorder with a high risk for embryonal tumors. It is mainly caused by dysregulation of imprinted genes on chromosome 11p15.5; however, the driving forces in the development of tumors are not fully understood.

PROCEDURE:

We report on a female patient presenting with macrosomia, macroglossia, organomegaly and extensive bilateral nephroblastomatosis. Adjuvant chemotherapy was initiated; however, the patient developed hepatoblastoma and Wilms tumor at 5 and 12 months of age, respectively. Subsequent radiofrequency ablation of the liver tumor and partial nephrectomy followed by consolidation therapy achieved complete remission.

RESULTS:

Molecular genetic analysis revealed a maternally derived large deletion of the complete H19-differentially methylated region (H19-DMR; imprinting control region-1 [ICR1]), the whole H19 gene itself as well as large parts of the distal enhancer region within the imprinting cluster-1 (IC1). Extended analysis showed highly elevated insulin-like growth factor 2 (IGF2) expression, possibly explaining at least in part the distinct BWS features and tumor manifestations.

CONCLUSIONS:

This study of a large maternal deletion encompassing the H19 gene and complete ICR1 is the first to demonstrate transcriptional consequences on IGF2 in addition to methylation effects resulting in severe overgrowth and occurrence of multiple tumors in a BWS patient. Studying this deletion helps to clarify the complex molecular processes involved in BWS and provides further insight into tumorigenesis.

KEYWORDS:

Beckwith-Wiedemann syndrome; embryonal tumors, imprinting and allele-specific expression; insulin-like growth factor 2, pediatric cancers

PMID:
27650505
DOI:
10.1002/pbc.26241
[Indexed for MEDLINE]

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