rs587779333
Variant summary
Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2PP3_StrongPP5_Very_Strong
The NM_001406875.1(PMS2):c.-674A>T variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,242 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).
Frequency
Consequence
NM_001406875.1 5_prime_UTR_premature_start_codon_gain
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 14 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD3 exomes AF: 0.00000400 AC: 1AN: 250222Hom.: 0 AF XY: 0.00 AC XY: 0AN XY: 135572
GnomAD4 exome AF: 6.85e-7 AC: 1AN: 1460242Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 726424
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
not provided Pathogenic:3
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Initiation codon variant in a gene for which loss-of-function is a known mechanism of disease; Observed in an individual with a history of a Lynch syndrome-related cancer and/or polyps and with a second PMS2 variant in a pediatric patient suspected of having constitutional mismatch repair deficiency (CMMR-D) syndrome (Yurgelun 2015, Adam 2016); Not observed at significant frequency in large population cohorts (gnomAD); Truncating variants in this gene are considered pathogenic by a well-established clinical consortium and/or database; This variant is associated with the following publications: (PMID: 18602922, 27476653, 28152038, 25980754, 23709753, 27742654, 27064304, 28466842, 26895986, 21376568, 29625052, 30787465, 29752822) -
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Hereditary cancer-predisposing syndrome Pathogenic:2
This variant results in the loss of the translation start codon of the PMS2 gene. Although functional studies have not been reported for this variant, this variant is expected to result in an absent or non-functional protein product. This variant has been reported in two individuals affected with PMS2-associated cancer or colorectal polyps (PMID: 25980754, 27476653) and in an individual affected with breast and ovarian cancer (PMID: 24130102). This variant has been identified in 1/250222 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Two different variants, c.1A>G and c.2T>A, that also disrupt the PMS2 translation start codon are known to be pathogenic (Clinvar variation ID: 91323 and 182809, respectively). Loss of PMS2 function is a known mechanism of disease. Based on available evidence, this variant is classified as Pathogenic. -
The p.M1? pathogenic mutation (also known as c.1A>T) is located in coding exon 1 of the PMS2 gene and results from an A to T substitution at nucleotide position 1. This alters the methionine residue at the initiation codon (ATG). This mutation was identified in a cohort of 1260 individuals undergoing panel testing for Lynch syndrome (Yurgelun MB et al. Gastroenterology 2015 Sep;149(3):604-13.e20) and in a cohort of Chinese breast cancer patients (Li JY et al. Int J Cancer 2019 01;144(2):281-289). This specific alteration has been reported in conjunction with PMS2 pathogenic mutations in individuals with constitutional mismatch repair deficiency (CMMR-D) phenotypes, although phase of the alterations was unknown (Adam R et al. Am J Hum Genet 2016 Aug;99(2):337-51; Ambry internal data). A similar alteration impacting the same nucleotide position (c.1A>G) has been reported in trans with a second pathogenic PMS2 mutation in three patients with CMMR-D who had absence of PMS2 staining observed in both tumor and normal tissues (Senter L et al. Gastroenterology 2008 Aug;135(2):419-28) and in an individual diagnosed with early-onset endometrial cancer demonstrating isolated loss of PMS2 by IHC analysis (Borràs E et al. J. Med. Genet. 2013 Aug;50:552-63). In addition to the clinical data presented in the literature, sequence variations that modify the initiation codon are expected to result in either loss of translation initiation, N-terminal truncation, or cause a shift in the mRNA reading frame. Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Lynch syndrome Pathogenic:1
This variant results in the loss of the translation start codon of the PMS2 gene. Although functional studies have not been reported for this variant, this variant is expected to result in an absent or non-functional protein product. This variant has been reported in an individual affected with Lynch syndrome-associated cancer or colorectal polyps (PMID: 25980754) and in individuals affected with breast and/or ovarian cancer (PMID: 24130102, 29752822). The variant has been observed with a second pathogenic PMS2 variant in individuals affected with clinical features of constitutional mismatch repair deficiency (PMID: 27476653, 30680046; ClinVar SCV000187260.9). In one of these individuals, the variants were confirmed in the compound heterozygous state, suggesting this variant is disease-causing (PMID: 30680046). This variant has been identified in 1/250222 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Two different variants, c.1A>G and c.2T>A, that also disrupt the PMS2 translation start codon are known to be pathogenic (Clinvar variation ID: 91323 and 182809, respectively). Loss of PMS2 function is a known mechanism of disease. Based on available evidence, this variant is classified as Pathogenic. -
Hereditary nonpolyposis colorectal neoplasms Pathogenic:1
This sequence change affects the initiator methionine of the PMS2 mRNA. The next in-frame methionine is located at codon 136. This variant is present in population databases (rs587779333, gnomAD 0.0009%). Disruption of the initiator codon has been observed in individuals with clinical features of Lynch syndrome and constitutional mismatch repair deficiency syndrome (PMID: 18602922, 20487569, 23709753, 24130102, 25559809, 25980754, 27476653; Invitae). ClinVar contains an entry for this variant (Variation ID: 142777). For these reasons, this variant has been classified as Pathogenic. -
Endometrial carcinoma Pathogenic:1
The p.Met1 (c.1A>T) variant in exon 1 of the PMS2 gene has not been reported in the literature nor previously identified by our laboratory. This variant did not show up in the databases (dbSNP, NHLBI Exome sequencing project (exome variant server), HGMD, LOVD, COSMIC, UMD, ClinVar, or BIC) and it is unknown if it may or may not be causative of the disorder. However it causes the loss of the start codon for exon 1. This residue has not been seen in mammals and computational analyses (PolyPhen2, SIFT, AlignGVGD) and it is unknown if this suggests a high likelihood of impact to the protein. However, this information is not predictive enough to rule out pathogenicity. In summary, the clinical significance of this variant cannot be determined with certainty at this time; however based upon the arguments described above, we find this variant to be PATHOGENIC. -
Lynch syndrome 4 Pathogenic:1
This variant is considered pathogenic. This variant is located within the gene translation start codon (p.Met1?) and is predicted to result in abnormal protein translation. This variant has been reported in multiple individuals with clinical features of gene-specific disease [PMID: 30680046, 27476653, 18602922]. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at