rs397508604

chr7-117642481-T-G

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.3761T>G(p.Leu1254Ter) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,461,408 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 (★★★). Synonymous variant affecting the same amino acid position (i.e. L1254L) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: CFTR NM_000492.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:7
• Conservation: PhyloP100: 7.54

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]

(HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-117642481-T-G is Pathogenic according to our data. Variant chr7-117642481-T-G is described in ClinVar as [Pathogenic]. Clinvar id is 53805.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr7-117642481-T-G is described in Lovd as [Pathogenic]. Variant chr7-117642481-T-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CFTR	NM_000492.4	c.3761T>G	p.Leu1254Ter	stop_gained	23/27	ENST00000003084.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CFTR	ENST00000003084.11	c.3761T>G	p.Leu1254Ter	stop_gained	23/27	1	NM_000492.4	P2
	ENST00000456270.1	n.65+4870A>C		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000684 AC: 10 AN: 1461408 Hom.: 0 Cov.: 32 AF XY: 0.00000550 AC XY: 4 AN XY: 726988

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: 0.00000810

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7

Revision: reviewed by expert panel

Submissions by phenotype

Cystic fibrosis Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Jul 06, 2022	The p.L1254* pathogenic mutation (also known as c.3761T>G), located in coding exon 23 of the CFTR gene, results from a T to G substitution at nucleotide position 3761. This changes the amino acid from a leucine to a stop codon within coding exon 23. This mutation has been identified in a cohort of Northern Irish cystic fibrosis families (Hughes DJ et al. Hum. Mutat., 1996;8:340-7). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Nov 17, 2023	This sequence change creates a premature translational stop signal (p.Leu1254*) 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). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with cystic fibrosis (PMID: 17331079). ClinVar contains an entry for this variant (Variation ID: 53805). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Dec 16, 2016	Variant summary: The CFTR c.3761T>G (p.Leu1254X) variant results in a premature termination codon, predicted to cause a truncated or absent CFTR 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. c.3773dupT/p.Leu1258fsX7). One in silico tool predicts a damaging outcome for this variant. This variant is absent in 121154 control chromosomes. This variant has been reported in multiple CF patients. In addition, CFTR2 classified this variant as pathogenic. Taken together, this variant is classified as pathogenic. -
Pathogenic, reviewed by expert panel	research	CFTR2	Mar 17, 2017	- -

Cystic fibrosis;C0403814:Congenital bilateral aplasia of vas deferens from CFTR mutation Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

-

- -

CFTR-related disorder Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Natera, Inc.

Mar 17, 2017

- -

Bronchiectasis with or without elevated sweat chloride 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Oct 17, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.65
Cadd	Pathogenic	40
Dann	Uncertain	0.99
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	A;A
Vest4		0.93
GERP RS		5.2

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs397508604; hg19: chr7-117282535; COSMIC: COSV99069639;