rs77035409

Variant names:

• chr7-117627741-AT-A
• rs77035409
• NM_000492.4:c.3691delT

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000492.4(CFTR):​c.3691delT​(p.Ser1231ProfsTer4) variant causes a frameshift change. The variant allele was found at a frequency of 0.000000685 in 1,460,418 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★★). Synonymous variant affecting the same amino acid position (i.e. S1231S) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CFTR NM_000492.4 frameshift
• Clinical Significance: Pathogenic reviewed by expert panel P:4
• Conservation: PhyloP100: 7.12
• 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)

ENSG00000083622 (HGNC:40145):

ACMG classification

Our verdict: Pathogenic. The variant received 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 7-117627741-AT-A is Pathogenic according to our data. Variant chr7-117627741-AT-A is described in ClinVar as Pathogenic. ClinVar VariationId is 35871.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CFTR	NM_000492.4	c.3691delT	p.Ser1231ProfsTer4	frameshift_variant	Exon 22 of 27	ENST00000003084.11	NP_000483.3
CFTR-AS2	NR_199597.1	n.66-11402delA		intron_variant	Intron 1 of 2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.3691delT	p.Ser1231ProfsTer4	frameshift_variant	Exon 22 of 27	1	NM_000492.4	ENSP00000003084.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460418 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726552

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33440

American (AMR) AF: 0.00 AC: 0 AN: 44684

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26112

East Asian (EAS) AF: 0.00 AC: 0 AN: 39652

South Asian (SAS) AF: 0.00 AC: 0 AN: 86236

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52860

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111346

Other (OTH) AF: 0.00 AC: 0 AN: 60330

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: reviewed by expert panel

Submissions by phenotype

Cystic fibrosis Pathogenic:3

Feb 27, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Ser1231Profs*4) in the CFTR gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CFTR are known to be pathogenic (PMID: 1695717, 7691345, 9725922). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with cystic fibrosis (PMID: 1710600, 27081564, 30548586). This variant is also known as CF3821delT. ClinVar contains an entry for this variant (Variation ID: 35871). 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. -

Oct 02, 2015

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Mar 17, 2017

CFTR2

Significance: Pathogenic

Review Status: reviewed by expert panel

Collection Method: research

- -

Bronchiectasis with or without elevated sweat chloride 1 Pathogenic:1

Feb 01, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.1
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.23		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.23		Position offset: 29

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

Other links and lift over

dbSNP: rs77035409; hg19: chr7-117267795;