7-117534275-G-C

Variant names:

• chr7-117534275-G-C
• rs397508734
• NM_000492.4:c.490-1G>C

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000492.4(CFTR):​c.490-1G>C variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000221 in 1,357,574 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 Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000022 (0 hom.)
• Consequence: CFTR NM_000492.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.08
• Publications: 1 publications found

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]

CFTR Gene-Disease associations (from GenCC):

• cystic fibrosis

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, Orphanet
• congenital bilateral absence of vas deferens

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary chronic pancreatitis

  Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.020256583 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.9, offset of 9, new splice context is: ttttcttttacactttaaAGctg. Cryptic site results in inframe 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 7-117534275-G-C is Pathogenic according to our data. Variant chr7-117534275-G-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1743994.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CFTR	NM_000492.4	c.490-1G>C		splice_acceptor_variant, intron_variant	Intron 4 of 26	ENST00000003084.11	NP_000483.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.490-1G>C		splice_acceptor_variant, intron_variant	Intron 4 of 26	1	NM_000492.4	ENSP00000003084.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000221 AC: 3 AN: 1357574 Hom.: 0 Cov.: 21 AF XY: 0.00000147 AC XY: 1 AN XY: 680942

African (AFR) AF: 0.00 AC: 0 AN: 31392

American (AMR) AF: 0.00 AC: 0 AN: 44436

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25372

East Asian (EAS) AF: 0.00 AC: 0 AN: 39102

South Asian (SAS) AF: 0.00 AC: 0 AN: 83354

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52316

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5526

European-Non Finnish (NFE) AF: 0.00000294 AC: 3 AN: 1019218

Other (OTH) AF: 0.00 AC: 0 AN: 56858

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cystic fibrosis Pathogenic:1

Jun 13, 2022

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.490-1G>C intronic variant (also known as 622-1G>C) results from a G to C substitution one nucleotide before coding exon 5 of the CFTR gene. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice acceptor site and will result in the creation or strengthening of a novel splice acceptor site. 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 likely pathogenic.

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

Jun 16, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.38
CADD	Pathogenic	36
DANN	Uncertain	1.0
DEOGEN2	Benign	0.0	.;.;.;.
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
LIST_S2	Benign	0.0	.;.;.;.
MetaRNN	Benign	0.0	.;.;.;.
MutationAssessor	Benign	0.0	.;.;.;.
PhyloP100		9.1
PROVEAN	Benign	0.0	.;.;.;.
Sift	Pathogenic	0.0	.;.;.;.
Sift4G	Pathogenic	0.0	.;.;.;.
Vest4		0.0
GERP RS		5.5
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
Splicevardb		3.0
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.98		Position offset: 10
DS_AL_spliceai		0.99		Position offset: 1

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

Other links and lift over

dbSNP: rs397508734; hg19: chr7-117174329;