16-68815760-G-C

Variant summary

Our verdict is Pathogenic. Variant got 22 ACMG points: 22P and 0B. PVS1 PM2 PP3_Strong PP5_Very_Strong

The NM_004360.5(CDH1):c.1565+1G>C variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,860 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CDH1 NM_004360.5 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic reviewed by expert panel P:4
• Conservation: PhyloP100: 9.33

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]

(HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 22 ACMG points.

• PVS1: Splicing variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 16-68815760-G-C is Pathogenic according to our data. Variant chr16-68815760-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 406622.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CDH1	NM_004360.5	c.1565+1G>C		splice_donor_variant		ENST00000261769.10
CDH1	NM_001317184.2	c.1382+1G>C		splice_donor_variant
CDH1	NM_001317185.2	c.17+1G>C		splice_donor_variant
CDH1	NM_001317186.2	c.-255+1G>C		splice_donor_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CDH1	ENST00000261769.10	c.1565+1G>C		splice_donor_variant		1	NM_004360.5	P1
	ENST00000563916.1	n.264-101C>G		intron_variant, non_coding_transcript_variant		4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461860 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727226

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: reviewed by expert panel

Submissions by phenotype

Hereditary diffuse gastric adenocarcinoma Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Dec 01, 2023	This sequence change affects a donor splice site in intron 10 of the CDH1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site 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). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individuals with hereditary diffuse gastric cancer (PMID: 26182300). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 406622). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. This variant disrupts the c.1565+1G nucleotide in the CDH1 gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 11968084, 18046629, 18788075, 26182300, 27064202, 27153395). This suggests that this nucleotide is clinically significant, and that variants that disrupt this position are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Jun 14, 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. -

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

Pathogenic, reviewed by expert panel

curation

ClinGen CDH1 Variant Curation Expert Panel

Aug 28, 2023

The c.1565+1G>C variant is a canonical splice variant predicted to result in a truncated or absent protein (PVS1_Strong, PM5_Supporting). The variant is absent in the gnomAD cohort (PM2_Supporting; http://gnomad.broadinstitute.org). This variant has been reported in at least four families meeting HDGC clinical criteria (PS4; PMID: 26182300, SCV000545383.5 and internal laboratory contributor). This variant was also found to co-segregate with disease in multiple affected family members, with at least nine meioses observed across four families (PP1_Strong; SCV000545383.5, SCV000665081.3 and internal laboratory contributor). 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, PS4, PP1_Strong, PM2_Supporting, PM5_Supporting. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 23, 2023

The c.1565+1G>C intronic pathogenic mutation results from a G to C substitution one nucleotide after coding exon 10 of the CDH1 gene. This alteration was identified in a proband with diffuse gastric cancer who had a family history of gastric cancer and lobular breast cancer (Hansford S et al. JAMA Oncol. 2015 Apr;1(1):23-32). In addition, two different splicing mutations at the same position, c.1565+1G>T and c.1565+1G>A, have previously been detected in families affected with hereditary diffuse gastric cancer (Humar B et al. Hum Mutat. 2002;19(5):518-25; Schrader KA et al. Fam Cancer. 2008;7:73-82; Huynh JM et al. Mol Genet Genomic Med. 2016 Mar;4(2):232-6). In addition to the clinical data presented in the literature, 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. RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). As such, this alteration is classified as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.36
Cadd	Pathogenic	36
Dann	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D;D
GERP RS		5.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.78		Position offset: 5
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: rs587780113; hg19: chr16-68849663; COSMIC: COSV99028501; COSMIC: COSV99028501;