rs397508740

Positions:

• chr7-117480098-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000492.4(CFTR):​c.4C>T​(p.Gln2Ter) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000137 in 1,461,704 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 Pathogenic (★★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CFTR NM_000492.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:9 O:1
• Conservation: PhyloP100: 3.85

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]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 1154 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-117480098-C-T is Pathogenic according to our data. Variant chr7-117480098-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 53980.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr7-117480098-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CFTR	NM_000492.4	c.4C>T	p.Gln2Ter	stop_gained	1/27	ENST00000003084.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CFTR	ENST00000003084.11	c.4C>T	p.Gln2Ter	stop_gained	1/27	1	NM_000492.4	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251152 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135750

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000545

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461704 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727168

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:9 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Cystic fibrosis Pathogenic:8 Other:1

not provided, no classification provided	literature only	ClinVar Staff, National Center for Biotechnology Information (NCBI)	-	- -
Pathogenic, criteria provided, single submitter	curation	CFTR-France	Jan 29, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Mendelics	Nov 05, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Apr 20, 2015	The p.Q2* mutation (also known as c.4C>T) located in coding exon 1 of the CFTR gene, results from a C to T substitution at nucleotide position 4. This changes the amino acid from a glutamine to a stop codon within coding exon 1. The first observation of this mutation was with p.R3W in a Bulgarian patient with lung disease, pancreatic insufficiency and at least one positive sweat test (Savov A 1994, Hum. Mol. Genet.; 3(1):57-60). In addition to the clinical data presented in the literature, since premature stop codons are typically deleterious in nature, this alteration is interpreted as a disease-causing mutation (ACMG Recommendations for Standards for Interpretation and Reporting of Sequence Variations. Revision 2007. Genet Med. 2008;10:294). -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jun 14, 2023	Variant summary: CFTR c.4C>T (p.Gln2X) results in a premature termination codon, predicted to cause an absence of the protein due to nonsense mediated decay, which is a commonly known mechanism for disease. The variant allele was found at a frequency of 4e-06 in 251152 control chromosomes. c.4C>T has been reported in the literature in individuals affected with Cystic Fibrosis (example, Savov_1994, Alonso_2007, Alper_2004, Trujillano_2013, Bresnick_2021). These data indicate that the variant is likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 17331079, 15365999, 34857524, 7512860, 23687349). Multiple clinical diagnostic laboratories and databases have submitted clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Johns Hopkins Genomics, Johns Hopkins University	Sep 15, 2019	Previously reported disease-causing CFTR variant. See www.CFTR2.org for phenotype information. -
Pathogenic, reviewed by expert panel	research	CFTR2	Mar 17, 2017	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 22, 2023	For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 53980). This premature translational stop signal has been observed in individual(s) with CFTR-related conditions (PMID: 7512860). This variant is present in population databases (rs397508740, gnomAD 0.006%). This sequence change creates a premature translational stop signal (p.Gln2*) in the CFTR gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CFTR are known to be pathogenic (PMID: 1695717, 7691345, 9725922). -

Bronchiectasis with or without elevated sweat chloride 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

May 12, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	39
DANN	Uncertain	1.0
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Uncertain	0.84	D
MutationTaster	Benign	1.0	A;A
Vest4		0.63
GERP RS		4.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs397508740; hg19: chr7-117120152;