rs397508158

Positions:

• chr7-117540347-G-A
• chr7-117540347-G-C
• chr7-117540347-G-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.1116+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,612,602 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: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: CFTR NM_000492.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic reviewed by expert panel P:11
• Conservation: PhyloP100: 9.42

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: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 6.6, offset of -34, new splice context is: atgGTatga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-117540347-G-A is Pathogenic according to our data. Variant chr7-117540347-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 53190.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr7-117540347-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CFTR	NM_000492.4	c.1116+1G>A		splice_donor_variant, intron_variant		ENST00000003084.11	NP_000483.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.1116+1G>A		splice_donor_variant, intron_variant		1	NM_000492.4	ENSP00000003084.6

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152108 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250560 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135424

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000884

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1460494 Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 2 AN XY: 726658

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152108 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74292

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:11

Revision: reviewed by expert panel

Submissions by phenotype

Cystic fibrosis Pathogenic:8

Pathogenic, criteria provided, single submitter	curation	CFTR-France	Jan 29, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 13, 2023	This sequence change affects a donor splice site in intron 8 of the CFTR 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 CFTR are known to be pathogenic (PMID: 1695717, 7691345, 9725922). This variant is present in population databases (rs397508158, gnomAD 0.0009%). Disruption of this splice site has been observed in individuals with cystic fibrosis (PMID: 10834512, 15365999, 21520337, 23974870, 30548586). This variant is also known as c.1248+1G>A. ClinVar contains an entry for this variant (Variation ID: 53190). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, reviewed by expert panel	research	CFTR2	Mar 17, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jun 20, 2019	Variant summary: CFTR c.1116+1G>A is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. 5/5 computational tools predict the variant abolishes a 5 splicing donor site and a significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 4e-06 in 250560 control chromosomes (gnomAD). The variant, c.1116+1G>A, has been reported in the literature in multiple individuals affected with Cystic Fibrosis or CBAVD (Kambouris_2000, Huber_2002, Kammesheidt_2006, Steiner_2011, Qiu_2018, Petrova_2019). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Three ClinVar submissions from other clinical diagnostic laboratories (evaluation after 2014) cite 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	Mar 10, 2023	Disease-causing CFTR variant. See www.CFTR2.org for phenotype information. -
Pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Jan 26, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Mendelics	Nov 05, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Mar 01, 2023	The c.1116+1G>A intronic pathogenic mutation results from a G to A substitution one nucleotide(s) after coding exon 8 of the CFTR gene. This alteration was identified in an individual with cystic fibrosis; however a second CFTR variant was not detected (Kambouris M et al. Eur. J. Pediatr., 2000 May;159:303-9). It was also identified in a cohort of individuals with congenital bilateral absence of the vas deferens (CBAVD) in conjunction with a second CFTR variant; however, the phase was not provided (Steiner B et al. Hum. Mutat., 2011 Aug;32:912-20). This alteration is also associated with elevated sweat chloride levels and pancreatic insufficiency (Sosnay PR et al. Nat. Genet., 2013 Oct;45:1160-7). Of note, this alteration is also known as 1248+1G>A in published literature. This nucleotide position is highly conserved in available vertebrate species. 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. 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. As such, this alteration is classified as a disease-causing mutation. -

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.

May 20, 2019

- -

Bronchiectasis with or without elevated sweat chloride 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Jul 29, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	35
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
GERP RS		5.3

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.89		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.69		Position offset: -35
DS_DL_spliceai		0.89		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: rs397508158; hg19: chr7-117180401;