1. A germline missense mutation in exon 3 of the MSH2 gene in a Lynch syndrome family: correlation with phenotype and localization assay
- Author
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Silvia Pagliaretta, Riccardo Giampieri, Federica Bini, Michela Del Prete, Francesco Piva, Marina Scarpelli, Rossana Berardi, L. Belvederesi, C. Brugiati, Elena Maccaroni, R. Bracci, Alessandra Mandolesi, and Francesca Bianchi
- Subjects
Adult ,Male ,0301 basic medicine ,Proband ,congenital, hereditary, and neonatal diseases and abnormalities ,Cancer Research ,Mutation, Missense ,Biology ,DNA Mismatch Repair ,03 medical and health sciences ,Exon ,Germline mutation ,Genetics ,medicine ,Humans ,Missense mutation ,Genetic Predisposition to Disease ,Multiplex ligation-dependent probe amplification ,Germ-Line Mutation ,Genetics (clinical) ,Aged ,Microsatellite instability ,Exons ,Middle Aged ,medicine.disease ,Colorectal Neoplasms, Hereditary Nonpolyposis ,Molecular biology ,digestive system diseases ,Lynch syndrome ,Gene Expression Regulation, Neoplastic ,MutS Homolog 2 Protein ,030104 developmental biology ,Oncology ,MSH2 ,Female ,Microsatellite Instability - Abstract
Lynch syndrome is caused by germline mutations in any of the MisMatch Repair (MMR) genes. About 37% of MSH2 variants are missense variants causing single amino-acid substitutions. Whether missense variants affect the normal function of MMR proteins is crucial both to provide affected families a more accurate risk assessment and to offer predictive testing to family members. Here we report one family, fulfilling both Amsterdam I and II criteria and Bethesda guidelines, referred to our center for genetic counselling. The proband and some of her relatives have been investigated for microsatellite instability (MSI), immunohistochemical MMR protein staining, direct sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA). Also Subcellular Localization Assay and Splice site predictions analyses were used. A germline missense variant of uncertain significance (exon 3, p.Val161Asp) was found in MSH2 gene in proband and in some relatives. The variant was associated with lack of expression of MSH2 protein (DMMR) and MSI-High status in tumour tissues. The localization assay of the MSH2 protein showed an abnormal subcellular localization pattern of the corresponding protein. Finally, splice-site prediction analysis ruled out a potential role of new splice sites as the cause behind the lack of expression of MSH2 protein and we suppose a potential correlation with other forms of post-transcriptional regulation (circular RNAs). The variant here reported shows a high correlation with phenotype and is located in an evolutionary conserved domain. The localization assay also suggest a potential pathogenic role, thus supporting further research on this matter.
- Published
- 2017
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