chr7-117480148-G-T

Position:

• chr7-117480148-G-T

Variant summary

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

The ENST00000003084.11(CFTR):​c.53+1G>T variant causes a splice donor change. The variant allele was found at a frequency of 0.00000274 in 1,461,636 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: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: CFTR ENST00000003084.11 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic reviewed by expert panel P:9
• Conservation: PhyloP100: 4.89

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 0.027458925 fraction of the gene. Cryptic splice site detected, with MaxEntScore 3.6, offset of 8, new splice context is: aagGTggcc. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-117480148-G-T is Pathogenic according to our data. Variant chr7-117480148-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 53988.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr7-117480148-G-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CFTR	NM_000492.4	c.53+1G>T		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.53+1G>T		splice_donor_variant		1	NM_000492.4	ENSP00000003084	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250350 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135382

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: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461636 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727128

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: 0.0000348

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:9

Revision: reviewed by expert panel

Submissions by phenotype

Cystic fibrosis Pathogenic:8

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 29, 2024	This sequence change affects a donor splice site in intron 1 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 (rs397508746, gnomAD 0.003%). Disruption of this splice site has been observed in individual(s) with cystic fibrosis and/or pancreatic insufficiency (PMID: 16596947, 22658665, 31126253, 32429104). This variant is also known as 185+1G>T. ClinVar contains an entry for this variant (Variation ID: 53988). 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, criteria provided, single submitter	clinical testing	Mendelics	Nov 05, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Suma Genomics	-	The splice variant c.53+1G>T (g.117480148G>T) is observed in intron 1 of CFTR in trans with another pathogenic variant. This variant is observed in the four individuals in the gnomAD database in heterozygous state. In-silico analysis tool SpliceAI predicts this variant in CFTR to cause aberrant splicing. ACMG classification: Pathogenic Criteria met: PVS1, PS4 and PM2_Supporting -
Pathogenic, criteria provided, single submitter	curation	CFTR-France	Jan 29, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 28, 2024	Variant summary: CFTR c.53+1G>T 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. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a 5' splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 4e-06 in 250350 control chromosomes. c.53+1G>T has been reported in the literature in multiple individuals affected with Cystic Fibrosis (e.g. Bienvenu_2005, Makukh_2010, Ooi_2012, Krenkova_2012, Ivady_2015). 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. The following publications have been ascertained in the context of this evaluation (PMID: 16596947, 20659818, 23276700, 22658665).ClinVar contains an entry for this variant (Variation ID: 53988). Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, reviewed by expert panel	research	CFTR2	Mar 17, 2017	- -
Likely pathogenic, criteria provided, single submitter	literature only	Counsyl	Oct 16, 2014	- -
Pathogenic, criteria provided, single submitter	clinical testing	Neuberg Centre For Genomic Medicine, NCGM	-	The splice site variant c.53+1G>T in CFTR gene has been observed in affected individuals (Krenkova P et.al.,2013). This variant has been reported to the ClinVar database as Pathogenic. The c.53+1G>T variant is novel (not in any individuals) in 1000 Genomes and allele frequency of 0.0004% is reported in gnomAD. The variant affects an invariant splice nucleotide and is expected to cause loss of function. Loss of function variants have been previously reported to be disease causing. For these reasons, this variant has been classified as Pathogenic. -

CFTR-related disorder Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Natera, Inc.

Mar 17, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Uncertain	0.90	D
MutationTaster	Benign	1.0	D;D
GERP RS		4.2

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.97		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.97		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: rs397508746; hg19: chr7-117120202;