chr7-117504277-AG-A

Variant names:

• chr7-117504277-AG-A
• rs397508798
• NM_000492.4:c.80delG

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_000492.4(CFTR):​c.80delG​(p.Gly27AspfsTer64) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000686 in 1,458,558 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as not provided (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: CFTR NM_000492.4 frameshift
• Clinical Significance: not provided no classification provided O:1
• Conservation: PhyloP100: 7.71
• 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 10 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 1221 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CFTR	NM_000492.4	c.80delG	p.Gly27AspfsTer64	frameshift_variant	Exon 2 of 27	ENST00000003084.11	NP_000483.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.80delG	p.Gly27AspfsTer64	frameshift_variant	Exon 2 of 27	1	NM_000492.4	ENSP00000003084.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1458558 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 725852

⚠️ 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: 33402

American (AMR) AF: 0.00 AC: 0 AN: 44710

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26088

East Asian (EAS) AF: 0.00 AC: 0 AN: 39612

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86188

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53410

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5750

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1109128

Other (OTH) AF: 0.00 AC: 0 AN: 60270

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: not provided

Submissions summary: Other:1

Revision: no classification provided

Submissions by phenotype

Cystic fibrosis Other:1

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ClinVar Staff, National Center for Biotechnology Information (NCBI)

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.7
Mutation Taster		=1/199	disease causing (fs/PTC)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs397508798; hg19: chr7-117144331;