rs387906359

Positions:

• chr7-117592583-G-GAT

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.2423_2424dup​(p.Ser809IlefsTer13) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CFTR NM_000492.4 frameshift
• Clinical Significance: Pathogenic reviewed by expert panel P:5
• Conservation: PhyloP100: 6.69

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: 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 7-117592583-G-GAT is Pathogenic according to our data. Variant chr7-117592583-G-GAT is described in ClinVar as [Pathogenic]. Clinvar id is 209046.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CFTR	NM_000492.4	c.2423_2424dup	p.Ser809IlefsTer13	frameshift_variant	14/27	ENST00000003084.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CFTR	ENST00000003084.11	c.2423_2424dup	p.Ser809IlefsTer13	frameshift_variant	14/27	1	NM_000492.4	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: reviewed by expert panel

Submissions by phenotype

Cystic fibrosis Pathogenic:5

Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Mar 25, 2022	The c.2423_2424dupAT pathogenic mutation (also known as CFTR ins2556insAT, c.2424_2425dupAT, c.2421_2422dupAT, and c.2422_2423insAT) is located in coding exon 14 of the CFTR gene and results from a duplication of AT at nucleotide position 2423, causing a translational frameshift with a predicted alternate stop codon (p.S809Ifs*13). This alteration was described in an individual with features of cystic fibrosis or a CFTR-related disorder (White MB et al. Nature, 1990 Apr;344:665-7). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). 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, no assertion criteria provided	literature only	OMIM	Apr 12, 1990	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Aug 29, 2020	For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in CFTR are known to be pathogenic (PMID: 1695717, 7691345, 9725922). This variant has been observed in individual(s) with clinical features of cystic fibrosis (CF) (PMID: 1691449). This variant is also known as CFIns2566 and 2556insAT. This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Ser809Ilefs*13) in the CFTR gene. It is expected to result in an absent or disrupted protein product. -
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	Jan 20, 2023	Variant summary: CFTR c.2423_2424dupAT (p.Ser809IlefsX13) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the 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. This variant is also reported as legacy name 2556insAT, and can be referred to as c.2424_2425dupAT, c.2421_2422dupAT, and c.2422_2423insAT. The variant was absent in 179966 control chromosomes (gnomAD). c.2423_2424dupAT has been reported in the literature and in CF patient databases in individuals affected with Cystic Fibrosis (e.g. White_1990, CFTR2 database). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Three submitters have provided clinical-significance assessments for this variant to ClinVar after 2014 and all classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs387906359; hg19: chr7-117232637;