7-117666937-C-G

Variant names:

• chr7-117666937-C-G
• rs1800135
• NM_000492.4:c.4272C>G

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000492.4(CFTR):​c.4272C>G​(p.Tyr1424*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. Y1424Y) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CFTR NM_000492.4 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: -2.86
• Publications: 12 publications found

Genes affected

CFTR (HGNC:1884): (CF transmembrane conductance regulator) This gene encodes a member of the ATP-binding cassette (ABC) transporter superfamily. The encoded protein functions as a chloride channel, making it unique among members of this protein family, and controls ion and water secretion and absorption in epithelial tissues. Channel activation is mediated by cycles of regulatory domain phosphorylation, ATP-binding by the nucleotide-binding domains, and ATP hydrolysis. Mutations in this gene cause cystic fibrosis, the most common lethal genetic disorder in populations of Northern European descent. The most frequently occurring mutation in cystic fibrosis, DeltaF508, results in impaired folding and trafficking of the encoded protein. Multiple pseudogenes have been identified in the human genome. [provided by RefSeq, Aug 2017]

CFTR Gene-Disease associations (from GenCC):

• cystic fibrosis

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, Orphanet
• congenital bilateral absence of vas deferens

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary chronic pancreatitis

  Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 28 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-117666937-C-G is Pathogenic according to our data. Variant chr7-117666937-C-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 371349.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CFTR	NM_000492.4	c.4272C>G	p.Tyr1424*	stop_gained	Exon 27 of 27	ENST00000003084.11	NP_000483.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.4272C>G	p.Tyr1424*	stop_gained	Exon 27 of 27	1	NM_000492.4	ENSP00000003084.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cystic fibrosis Pathogenic:3

May 26, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the CFTR protein in which other variant(s) (p.Ser1455*) have been determined to be pathogenic (PMID: 17662673, 23276700, 24388274, 25304080, 27728908). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 371349). A different variant (c.4272C>A) giving rise to the same protein effect has been determined to be pathogenic (Invitae). This suggests that this variant is also likely to be causative of disease. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Tyr1424*) in the CFTR gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 57 amino acid(s) of the CFTR protein.

Sep 16, 2020

Natera, Inc.

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

Sep 01, 2016

Counsyl

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.

not specified Pathogenic:1

Nov 05, 2018

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: CFTR c.4272C>G (p.Tyr1424X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory (e.g., p.Ser1455X and p.Gln1476X). The variant was absent in 245554 control chromosomes. c.4272C>G has been reported in the literature in individuals with deltaF508 on the alternate allele and were affected with mild Cystic Fibrosis and pancreatic sufficiency, suggesting the variant is a mild causative mutation. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.38
CADD	Uncertain	24
DANN	Benign	0.95
DEOGEN2	Benign	0.0	.;.;.
Eigen	Benign	-0.77
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.19	N
LIST_S2	Benign	0.0	.;.;.
MetaRNN	Benign	0.0	.;.;.
MutationAssessor	Benign	0.0	.;.;.
PhyloP100		-2.9
PROVEAN	Benign	0.0	.;.;.
REVEL	Benign	0.0
Sift	Pathogenic	0.0	.;.;.
Sift4G	Pathogenic	0.0	.;.;.
Vest4		0.88
GERP RS		-9.6
Mutation Taster		=1/199	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs1800135; hg19: chr7-117306991;