Project description:Beckwith-Wiedemann Spectrum (BWSp) is a disorder predisposing to tumors of embryonic origin that arise during childhood. Little is known concerning the tumor risk and histotype prevalence in adult BWSp patients. However, several studies report cases of co-occurrence of BWSp and tumors in early adulthood, suggesting that the cancer risk in BWSp could be relevant also later than childhood. Here, we report for the first time a case of co-occurrence of BWSp and early-onset colorectal cancer (EO-CRC). The results disclosed genetic and epigenetic molecular lesions of the patient at both somatic and germline levels, providing support to the hypothesis that epigenetic changes contribute to cancer initiation in tissues where a genetic insult is already present, acting in a cooperative manner to stimulate tumorigenesis.
Project description:PADI6 is a component of the subcortical maternal complex (SCMC) which is a group of proteins that are abundantly expressed in the oocyte cytoplasm and essential for the proper development of the early embryo. The mutation(s) in the components of the subcortical maternal complex have been associated with reproductive failures, including formation of hydatidiform mole, female infertility and imprinting disorders with multi-locus imprinting disturbance (MLIDs).In the current study by using whole-exome sequencing analysis, we identified four cases of Beckwith-Wiedemann Syndrome with multi-locus imprinting disturbance while their mothers were carriers of variants in PADI6 gene. Genome-wide methylation profiling using Methylation EPIC array depicted the loss of methylation specifically at several known imprinted loci in affected individuals as compared to healthy siblings, parents and controls. Our findings firmly establish the role of PADI6 in imprinting disorders.
Project description:The use of assisted reproductive technologies (ART) can induce a congenital overgrowth condition in humans and ruminants, namely Beckwith-Wiedemann syndrome (BWS) and large offspring syndrome (LOS), respectively. Shared phenotypes and epigenotypes have been found between BWS and LOS. We have observed global misregulation of transcripts in bovine foetuses with LOS. microRNAs (miRNAs) are important post-transcriptional gene expression regulators. We hypothesize that there is miRNA misregulation in LOS and that this misregulation is shared with BWS. In this study, small RNA sequencing was conducted to investigate miRNA expression profiles in bovine and human samples. We detected 407 abundant known miRNAs and predicted 196 putative miRNAs from the bovine sequencing results and identified 505 abundant miRNAs in human tongue. Differentially expressed miRNAs (DE-miRNAs) were identified between control and LOS groups in all tissues analysed as well as between BWS and control human samples. DE-miRNAs were detected from several miRNA clusters including DLK1-DIO3 genomic imprinted cluster in LOS and BWS. DNA hypermethylation was associated with downregulation of miRNAs in the DLK1-DIO3. mRNA targets of the DE-miRNAs were predicted and signalling pathways associated with control of organ size (including the Hippo signalling pathway), cell proliferation, apoptosis, cell survival, cell cycle, and cell adhesion were found to be enriched with these genes. Yes associated protein 1 (YAP1) is the core effector of the Hippo signalling pathway, and increased level of active (non-phosphorylated) YAP1 protein was detected in skeletal muscle of LOS foetuses. Overall, our data provide evidence of miRNA misregulation in LOS and BWS.
Project description:We report RNAseq profiles of an individual carrying a maternally inherited splice variant in the first intron of the KCNQ1 gene and displaying complete loss of methylation at KCNQ1OT1:TSS DMR, the Imprinting Control Region of the centromeric domain of the Beckwith-Wiedemann locus. The half-sister was used as control. We show that the most 5’ 10 kb of KCNQ1 is about 2-3-fold more abundant than the rest of the gene in the proband, while RNA level was homogeneously distributed along the entire gene in the control. These results are consistent with data obtained from locus-specific analyses and overall suggest that premature termination of the KCNQ1 gene is occurring in cis with the splice variant and is associated with lack of methylation of the KCNQ1OT1:TSS DMR on the maternal chromosome.
Project description:Imprinting disorders are congenital diseases caused by dysregulation of genomic imprinting, affecting growth, neurocognitive development, metabolism and cancer predisposition. Overlapping clinical features are often observed among this group of diseases. In rare cases, two fully expressed imprinting disorders may coexist in the same patient. A dozen cases of this type have been reported so far. Most of them are represented by individuals affected by Beckwith-Wiedemann spectrum (BWSp) and Transient Neonatal Diabetes Mellitus (TNDM) or BWSp and Pseudo-hypoparathyroidism type 1B (PHP1B). All these patients displayed multilocus imprinting disturbances (MLID). Here, we report the first case of co-occurrence of BWS and PHP1B in the same individual in absence of MLID. Genome-wide methylation and SNP-array analyses demonstrated loss of methylation of the KCNQ1OT1:TSS-DMR on chromosome 11p15.5 as molecular cause of BWSp, and upd(20)pat as cause of PHP1B. The absence of MLID and the heterodisomy of chromosome 20 suggests that BWSp and PHP1B arose through distinct and independent mechanism in our patient.