7-117590441-T-A

Position:

• chr7-117590441-T-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000492.4(CFTR):​c.1766+2T>A variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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 Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CFTR NM_000492.4 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 7.41

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 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.01935629 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-117590441-T-A is Pathogenic according to our data. Variant chr7-117590441-T-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 557448.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CFTR	NM_000492.4	c.1766+2T>A		splice_donor_variant		ENST00000003084.11	NP_000483.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.1766+2T>A		splice_donor_variant		1	NM_000492.4	ENSP00000003084	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cystic fibrosis Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Mar 26, 2018	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Jan 03, 2024	The c.1766+2T>A intronic variant results from a T to A substitution two nucleotides after coding exon 13 in the CFTR gene. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. The resulting transcript is predicted to be in-frame and is not expected to trigger nonsense-mediated mRNAdecay; however, direct evidence is unavailable. The exact functional effect of the altered amino acid sequence is unknown; however, the impacted region is critical for protein function (Ambry internal data). This variant was identified in two alleles in a cohort of individuals with cystic fibrosis (Raraigh KS et al. J Cyst Fibros, 2022 May;21:463-470). This nucleotide position is highly conserved in available vertebrate species. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jun 15, 2022	For these reasons, this variant has been classified as Pathogenic. Studies have shown that disruption of this splice site results in skipping of exon 13, but is expected to preserve the integrity of the reading-frame (PMID: 1284540). ClinVar contains an entry for this variant (Variation ID: 557448). Disruption of this splice site has been observed in individuals with cystic fibrosis (PMID: 1284540, 20052365, 24586523). This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 13 of the CFTR gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Aug 31, 2018

- -

Cystic fibrosis;C0238339:Hereditary pancreatitis;C0403814:Congenital bilateral aplasia of vas deferens from CFTR mutation;C2749757:Bronchiectasis with or without elevated sweat chloride 1 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Feb 15, 2022

- -

CFTR-related disorder Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

Natera, Inc.

Jun 26, 2019

- -

Bronchiectasis with or without elevated sweat chloride 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Mar 06, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.37
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	D;D
GERP RS		4.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.86		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.86		Position offset: -2

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

Publications

LitVar

Other links and lift over

dbSNP: rs1554389062; hg19: chr7-117230495;