Submissions for variant NM_000249.4(MLH1):c.1667G>A (p.Ser556Asn)

dbSNP: rs63751596

Total submissions: 7

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
GeneDx	RCV000520479	SCV000618169	likely pathogenic	not provided	2019-09-10	criteria provided, single submitter	clinical testing	Not observed in large population cohorts (Lek 2016); Observed in individuals with a personal or family history consistent with pathogenic variants in this gene (Whitworth 2015, Sjursen 2016, Yurgelun 2017); This variant is associated with the following publications: (PMID: 25248401, 27064304, 22949387, 28135145, 30521064, 30720243)
Ambry Genetics	RCV001012628	SCV001173105	pathogenic	Hereditary cancer-predisposing syndrome	2021-02-23	criteria provided, single submitter	clinical testing	The c.1667G>A pathogenic mutation (also known as p.S556N), located in coding exon 14 of the MLH1 gene, results from a G to A substitution at nucleotide position 1667. The amino acid change results in serine to asparagine at codon 556, an amino acid with highly similar properties. However, this change occurs in the last base pair of coding exon 14, which makes it likely to have some effect on normal mRNA splicing. This alteration has been identified in multiple families fulfilling Amsterdam criteria (Sjursen W et al. Mol Genet Genomic Med. 2016 Mar;4:223-31; Yurgelun MBJ. Clin. Oncol. 2017 Apr;35(10):1086-1095; Jiang W et al. Int J Cancer, 2019 05;144:2161-2168). Another alteration at this same nucleotide position, c.1667G>T, has been shown to result in the use of a cryptic splice site that leads to a frameshift predicted to create a truncated protein (Sharp et al. Hum Mutat. 2004 Sep;24(3):272; Desmet et al. Nucleic Acids Res. 2009 May;37(9):e67). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation.
Invitae	RCV001046224	SCV001210118	pathogenic	Hereditary nonpolyposis colorectal neoplasms	2023-12-29	criteria provided, single submitter	clinical testing	This sequence change replaces serine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 556 of the MLH1 protein (p.Ser556Asn). This variant also falls at the last nucleotide of exon 14, which is part of the consensus splice site for this exon. This variant is present in population databases (no rsID available, gnomAD 0.0009%). This missense change has been observed in individuals with colorectal cancer and clinical features of Lynch syndrome (PMID: 27064304, 28135145; Invitae; externalcommunication). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 449776). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic.
CeGaT Center for Human Genetics Tuebingen	RCV000520479	SCV004011452	likely pathogenic	not provided	2023-04-01	criteria provided, single submitter	clinical testing	MLH1: PM1, PM2, PS4:Moderate, PP1
Baylor Genetics	RCV003470652	SCV004193051	likely pathogenic	Colorectal cancer, hereditary nonpolyposis, type 2	2022-04-20	criteria provided, single submitter	clinical testing
Ding PR Lab, Sun Yat-sen University Cancer Center	RCV001093684	SCV001250865	uncertain significance	Lynch syndrome 1		no assertion criteria provided	clinical testing
Constitutional Genetics Lab, Leon Berard Cancer Center	RCV001249931	SCV001423873	likely pathogenic	Lynch-like syndrome	2019-07-01	no assertion criteria provided	clinical testing