7-6009019-T-G
Variant summary
Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PVS1PS1_ModeratePM2PP5_Very_Strong
The NM_000535.7(PMS2):c.1A>C(p.Met1?) variant causes a initiator codon change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,226 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_000535.7 initiator_codon
Scores
Clinical Significance
Conservation
Publications
- leukodystrophy, hypomyelinating, 17Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Illumina, Labcorp Genetics (formerly Invitae)
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ACMG classification
Our verdict: Pathogenic. The variant received 20 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| PMS2 | NM_000535.7 | c.1A>C | p.Met1? | initiator_codon_variant | Exon 1 of 15 | ENST00000265849.12 | NP_000526.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| PMS2 | ENST00000265849.12 | c.1A>C | p.Met1? | initiator_codon_variant | Exon 1 of 15 | 1 | NM_000535.7 | ENSP00000265849.7 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152226Hom.: 0 Cov.: 32 show subpopulations
GnomAD4 exome Cov.: 32
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152226Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74368 show subpopulations
ClinVar
Submissions by phenotype
not provided Pathogenic:2
This variant disrupts the translation initiation codon of the PMS2 mRNA and is predicted to interfere with PMS2 protein synthesis. The frequency of this variant in the general population, 0.000032 (1/31402 chromosomes, http://gnomad.broadinstitute.org), is uninformative in assessment of its pathogenicity. In the published literature, the variant has not been reported in individuals with a PMS2-related disorder. However, other start loss variants affecting the same codon have been reported in affected patients with suspected Lynch Syndrome (PMIDs: 18602922 (2008), 23709753 (2014), 27742654 (2017), and 28466842 (2017)). Based on the available information, this variant is classified as likely pathogenic.
Initiation codon variant in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 38654521, 18602922, 23709753, 27476653, 28466842)
Hereditary nonpolyposis colon cancer Pathogenic:1
Variant summary: PMS2 c.1A>C (p.Met1Leu) alters the initiation codon and is predicted to result either in absence of the protein or truncation of the encoded protein due to translation initiation at a downstream codon. Two of three in-silico tools predict a benign effect of the variant on protein function. The next downstream in-frame ATG start site is at codon 136 (Exon 5). Other variants impacting the PMS2 initiation codon, including c.1A>G (p.Met1Val), c.2T>C (p.Met1Thr), and c.2T>A (p.Met1Lys), as well as missense and truncating variants upstream of the potential new initiation codon have been classified as pathogenic by our lab and in ClinVar, and reported in association with Lynch syndrome-associated cancers in HGMD. The variant was absent in 250222 control chromosomes (gnomAD). To our knowledge, no occurrence of c.1A>C in individuals affected with Lynch Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Three submitters have reported clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as likely 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 (no rsID available, gnomAD 0.03%). Disruption of the initiator codon has been observed in individuals with PMS2-related conditions (PMID: 18602922, 20487569, 23709753; Invitae). ClinVar contains an entry for this variant (Variation ID: 820477). For these reasons, this variant has been classified as Pathogenic.
Hereditary cancer-predisposing syndrome Pathogenic:1
The p.M1? pathogenic mutation (also known as c.1A>C) is located in coding exon 1 of the PMS2 gene and results from an A to C substitution at nucleotide position 1. This alters the methionine residue at the initiation codon (ATG). Other alterations impacting the PMS2 initiation codon have been reported in individuals with early-onset, Lynch syndrome-associated malignancies and tumors demonstrating isolated loss of PMS2 staining by immunohistochemistry (IHC) (Senter et al. Gastroenterology. 2008 Aug;135(2):419-28; Borràs E, J. Med. Genet. 2013 Aug; 50(8):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 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