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se of the disease is still unknown. Using exome sequencing in combination with linkage analyses together with detection of copy-number variations (CNV), we have identified a duplication in the regulatory region of the GREM1 gene in a family with an attenuated/atypical polyposis syndrome. In addition, 107 patients with colorectal cancer and/or polyposis were analyzed for mutations in the candidate genes identified. We also performed screening of the exonuclease domain of the POLE gene in a subset of these patients. The duplication of 16 kb in the regulatory region of GREM1 was found to be disease-causing in the family. Functional analyses revealed a higher expression of the GREM1 gene in colorectal tissue in duplication carriers. Screening of the exonuclease domain of POLE in additional CRC patients identified a probable causative novel variant c.1274A>G, p.Lys425Arg. In conclusion a high penetrant duplication in the regulatory region of GREM1, predisposing to CRC, was identified in a family with attenuated/atypical polyposis. A POLE variant was identified in a patient with early onset CRC and a microsatellite stable (MSS) tumor. Mutations leading to increased expression of genes can constitute disease-causing mutations in hereditary CRC syndromes.

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implicated in the aetiology of this common developmental anomaly in the Polish population. METHODS: Eight polymorphisms were genotyped in 334 NSCL/P patients and 955 controls. In addition, the GREM1 protein-coding region was sequenced in 96 NSCL/P patients. RESULTS: Significant association with a risk of oral clefts was found for 5 tested polymorphisms. The lowest p(trend) values were identified for rs16969681, rs16969816, and rs1258763 (p(trend) 4.09E-05, 3.35E-05, and 0.0002, respectively). The putative functional variant rs16969681, located in a region that has enhancer activity, was associated with a 2.6-fold lower risk for NSCL/P (odds ratio [OR] = 0.38; 95% confidence interval [CI], 0.24-0.61, p = 2.37E-05). The previously reported association of rs1258763 with NSCL/P was replicated (OR = 0.57; 95% CI, 0.44-0.73; p = 1.10E-05). For all tested GREM1 variants, no significant sex-by-genotype interaction effects were observed. The sequencing analysis did not detect any rare variants implicated in the development of oral clefts. CONCLUSION: Our results might suggest that variants influencing GREM1 expression levels, rather than variants affecting the function of the encoded protein, are significant factors in NSCL/P etiology.

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e involvement are largely unknown. In this study, we carried out a meta-analysis on genetic and clinical data from three large cohorts and identified strong association between a region on chromosome 15q13 and nsCLP (P = 8.13 x 10(-14) for rs1258763; relative risk (RR): 1.46, 95% confidence interval (CI): 1.32-1.61)) but not nsCLO (P = 0.27; RR: 1.09 (0.94-1.27)). The 5 kb region of strongest association maps downstream of Gremlin-1 (GREM1), which encodes a secreted antagonist of the BMP4 pathway. We show during mouse embryogenesis, Grem1 is expressed in the developing lip and soft palate but not in the hard palate. This is consistent with genotype-phenotype correlations between rs1258763 and a specific nsCLP subphenotype, since a more than two-fold increase in risk was observed in patients displaying clefts of both the lip and soft palate but who had an intact hard palate (RR: 3.76, CI: 1.47-9.61, Pdiff<0.05). While we did not find lip or palate defects in Grem1-deficient mice, wild type embryonic palatal shelves developed divergent shapes when cultured in the presence of ectopic Grem1 protein (P = 0.0014). The present study identified a non-coding region at 15q13 as the second, genome-wide significant locus specific for nsCLP, after 13q31. Moreover, our data suggest that the closely located GREM1 gene contributes to a rare clinical nsCLP entity. This entity specifically involves abnormalities of the lip and soft palate, which develop at different time-points and in separate anatomical regions.