16-68810342-G-A

Position:

• chr16-68810342-G-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Strong PS3 PS4_Moderate PM5_Supporting PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The CDH1 c.832+1G>A variant is a canonical splice variant in intron 6 predicted to result in a truncated or absent protein (PVS1_Strong, PM5_Supporting). The variant is absent from the gnomAD cohort (PM2_Supporting; http://gnomad.broadinstitute.org). This variant has been observed in three families meeting IGCLC criteria for HDGC (PS4_Moderate, internal clinical lab data). This variant has also been reported in the literature in families with LBC who do not meet criteria for HDGC (PMID:36436516, 32489267, 34643667). RNA analysis demonstrated two out-of-frame transcripts, r.754_832del79 p.(V252Efs*4) and r.688_832del145 p.(L230Efs*4) (PS3; internal clinical lab data). In summary, this variant meets criteria to be classified as pathogenic based on the ACMG/AMP criteria applied as specified by the CDH1 Variant Curation Expert Panel (Variant Interpretation Guidelines Version 3.1): PVS1_Strong, PS3, PS4_Moderate, PM2_Supporting, PM5_Supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA396459027/MONDO:0007648/007

• Frequency: Genomes: not found (cov: 32)
• Consequence: CDH1 NM_004360.5 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic reviewed by expert panel P:9
• Conservation: PhyloP100: 8.89

Genes affected

CDH1 (HGNC:1748): (cadherin 1) This gene encodes a classical cadherin of the cadherin superfamily. Alternative splicing results in multiple transcript variants, at least one of which encodes a preproprotein that is proteolytically processed to generate the mature glycoprotein. This calcium-dependent cell-cell adhesion protein is comprised of five extracellular cadherin repeats, a transmembrane region and a highly conserved cytoplasmic tail. Mutations in this gene are correlated with gastric, breast, colorectal, thyroid and ovarian cancer. Loss of function of this gene is thought to contribute to cancer progression by increasing proliferation, invasion, and/or metastasis. The ectodomain of this protein mediates bacterial adhesion to mammalian cells and the cytoplasmic domain is required for internalization. This gene is present in a gene cluster with other members of the cadherin family on chromosome 16. [provided by RefSeq, Nov 2015]

CDH1 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: For more information check the summary or visit ClinGen Evidence Repository.
• PS3: For more information check the summary or visit ClinGen Evidence Repository.
• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM5: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CDH1	NM_004360.5	c.832+1G>A		splice_donor_variant, intron_variant		ENST00000261769.10	NP_004351.1
CDH1	NM_001317184.2	c.832+1G>A		splice_donor_variant, intron_variant			NP_001304113.1
CDH1	NM_001317185.2	c.-784+1G>A		splice_donor_variant, intron_variant			NP_001304114.1
CDH1	NM_001317186.2	c.-988+1G>A		splice_donor_variant, intron_variant			NP_001304115.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CDH1	ENST00000261769.10	c.832+1G>A		splice_donor_variant, intron_variant		1	NM_004360.5	ENSP00000261769.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:9

Revision: reviewed by expert panel

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Nov 09, 2023	The c.832+1G>A pathogenic intronic mutation results from a G to A substitution one nucleotide after coding exon 6 of the CDH1 gene. This nucleotide position is highly conserved in available vertebrate species. Another mutation at this position (c.832+1G>T) was reported in a 17-year-old patient with diffuse gastric cancer and history of cleft lip with cleft palate, and in a proband with a personal and family history of diffuse gastric cancer (Benusiglio PR et al. Int. J. Cancer 2013 May;132:2470; Ambry internal data). In silico splice site analysis predicts that this alteration will weaken the native splice donor site and will result in the creation or strengthening of a novel splice donor site. RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). In addition to the available clinical data, alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation. -
Pathogenic, criteria provided, single submitter	clinical testing	Department of Molecular Diagnostics, Institute of Oncology Ljubljana	Oct 24, 2018	- -
Pathogenic, no assertion criteria provided	clinical testing	BRCAlab, Lund University	Aug 26, 2022	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Oct 15, 2019	This variant causes a G>A nucleotide substitution at the +1 position of intron 6 of the CDH1 gene. Splice site prediction tools predict that this variant may have a significant impact on RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of CDH1 function is a known mechanism of disease. Based on the available evidence, this variant is classified as Likely Pathogenic. -

Hereditary diffuse gastric adenocarcinoma Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Mar 26, 2021	Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. For these reasons, this variant has been classified as Pathogenic. Donor and acceptor splice site variants typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in CDH1 are known to be pathogenic (PMID: 15235021, 20373070). Disruption of this splice site has been observed in individual(s) with diffuse gastric cancer (PMID: 23124477, 23709761, 26182300). ClinVar contains an entry for this variant (Variation ID: 463795). This variant is not present in population databases (ExAC no frequency). This sequence change affects a donor splice site in intron 6 of the CDH1 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Jun 12, 2023	This variant is considered likely pathogenic. This variant occurs within a consensus splice junction and is predicted to result in abnormal mRNA splicing of either an out-of-frame exon or an in-frame exon necessary for protein stability and/or normal function. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Aug 10, 2019

The CDH1 c.832+1G>A variant, to our knowledge, is not reported in the medical literature but is reported as likely pathogenic/pathogenic in ClinVar (Variation ID: 463795). This variant is absent from general population databases (Exome Variant Server, Genome Aggregation Database), indicating it is not a common polymorphism. A different variant at this codon, c.832+1G>T, is reported in the literature in an individual with hereditary diffuse gastric cancer (Benusiglio 2013). This is an intronic variant in a highly conserved nucleotide, and computational analyses (Alamut v.2.11) predict that this variant may impact splicing by abolishing the nearby canonical donor splice site. Based on available information, this variant is considered to be pathogenic. REFERENCES Benusiglio PR et al. Cleft lip, cleft palate, hereditary diffuse gastric cancer and germline mutations in CDH1. Int J Cancer. 2013 May 15;132(10):2470. -

CDH1-related diffuse gastric and lobular breast cancer syndrome Pathogenic:1

Pathogenic, reviewed by expert panel

curation

ClinGen CDH1 Variant Curation Expert Panel

Mar 25, 2024

The CDH1 c.832+1G>A variant is a canonical splice variant in intron 6 predicted to result in a truncated or absent protein (PVS1_Strong, PM5_Supporting). The variant is absent from the gnomAD cohort (PM2_Supporting; http://gnomad.broadinstitute.org). This variant has been observed in three families meeting IGCLC criteria for HDGC (PS4_Moderate, internal clinical lab data). This variant has also been reported in the literature in families with LBC who do not meet criteria for HDGC (PMID: 36436516, 32489267, 34643667). RNA analysis demonstrated two out-of-frame transcripts, r.754_832del79 p.(V252Efs*4) and r.688_832del145 p.(L230Efs*4) (PS3; internal clinical lab data). In summary, this variant meets criteria to be classified as pathogenic based on the ACMG/AMP criteria applied as specified by the CDH1 Variant Curation Expert Panel (Variant Interpretation Guidelines Version 3.1): PVS1_Strong, PS3, PS4_Moderate, PM2_Supporting, PM5_Supporting. -

Malignant tumor of breast Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The CDH1 c.832+1G>A variant was identified in 1 of 86 proband chromosomes (frequency: 0.01) from individuals or families with diffuse gastric cancer (Brooks-Wilson 2004). The variant was also identified in ClinVar (classified as likely pathogenic by Invitae) and Cosmic (2x in breast tissue). The variant was not identified in dbSNP, the Zhejiang University Database, or the following control databases: the 1000 Genomes Project, the NHLBI GO Exome Sequencing Project, the Exome Aggregation Consortium (August 8th 2016), or the Genome Aggregation Database (Feb 27, 2017). The c.832+1G>A variant is predicted to cause abnormal splicing because the nucleotide substitution occurs in the invariant region of the splice consensus sequence. In addition, 4 of 4 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) predict a greater than 10% difference in splicing. It is predicted that the aberrant splicing would result in an in-frame deletion of exon 5 from the transcript, which is expected to be deleterious to the protein function (Brooks-Wilson 2004). In summary, based on the above information, this variant meets our laboratory’s criteria to be classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	35
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.92
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	D;D
GERP RS		5.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.66		Position offset: -13
DS_DL_spliceai		0.99		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs878854697; hg19: chr16-68844245; COSMIC: COSV55728175; COSMIC: COSV55728175;