rs759726535

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1PM2PP3

The NM_000492.4(CFTR):c.76A>G(p.Lys26Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000011 in 1,458,278 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

CFTR
NM_000492.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:7

Conservation

PhyloP100: 7.20

Variant links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 5 ACMG points.

PM1

In a topological_domain Cytoplasmic (size 76) in uniprot entity CFTR_HUMAN there are 14 pathogenic changes around while only 2 benign (88%) in NM_000492.4

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.8

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CFTR	NM_000492.4 link	c.76A>G	p.Lys26Glu	missense_variant	Exon 2 of 27	ENST00000003084.11	NP_000483.3	P13569-1A0A024R730

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11 link	c.76A>G	p.Lys26Glu	missense_variant	Exon 2 of 27	1	NM_000492.4	ENSP00000003084.6		P13569-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000159

AC:

AN:

250942

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135612

show subpopulations

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:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000353

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000110

AC:

AN:

1458278

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

725726

show subpopulations

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:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000117

Gnomad4 OTH exome

AF:

0.0000332

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000301

Hom.:

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00

AC:

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cystic fibrosis

Uncertain:4

Jan 07, 2020

Johns Hopkins Genomics, Johns Hopkins University

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

CFTR c.76A>G was identified in a single unpublished patient who is reported to have congenital bilateral absence of the vas deferens. It is classified as a variant of uncertain clinical significance in ClinVar by a single submitter. This variant (rs759726535) is rare (<0.1%) in a large population dataset (gnomAD: 4/250942 total alleles; 0.0016%; no homozygotes). Of three bioinformatics tools queried, one predicts that the substitution would probably be damaging, while two predict that it would be tolerated. The lysine residue at this position is conserved in all species assessed. We consider the clinical significance of c.76A>G to be uncertain at this time. -

Sep 01, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces lysine with glutamic acid at codon 26 of the CFTR protein (p.Lys26Glu). The lysine residue is moderately conserved and there is a small physicochemical difference between lysine and glutamic acid. This variant is present in population databases (rs759726535, ExAC 0.003%). This variant has not been reported in the literature in individuals affected with CFTR-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Sep 05, 2021

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 01, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.K26E variant (also known as c.76A>G), located in coding exon 2 of the CFTR gene, results from an A to G substitution at nucleotide position 76. The lysine at codon 26 is replaced by glutamic acid, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

CFTR-related disorder

Uncertain:2

Aug 24, 2023

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The CFTR c.76A>G variant is predicted to result in the amino acid substitution p.Lys26Glu. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.0035% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/7-117144329-A-G). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Oct 26, 2018

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

not specified

Uncertain:1

Jun 04, 2021

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: CFTR c.76A>G (p.Lys26Glu) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.6e-05 in 250942 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.76A>G in individuals affected with Cystic Fibrosis and no experimental evidence demonstrating its impact on protein function have been reported in the literature. Two other clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Both laboratories cited the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.38

BayesDel_addAF

Pathogenic

0.44

BayesDel_noAF

Pathogenic

0.46

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.52

D;.;.;T;.

Eigen

Pathogenic

0.86

Eigen_PC

Pathogenic

0.79

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.90

D;D;D;D;D

M_CAP

Pathogenic

0.49

MetaRNN

Pathogenic

0.80

D;D;D;D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.4

M;.;.;.;M

PrimateAI

Uncertain

0.56

PROVEAN

Benign

-2.1

N;.;.;N;.

REVEL

Pathogenic

0.73

Sift

Benign

0.073

T;.;.;T;.

Sift4G

Pathogenic

0.0

D;.;.;D;.

Polyphen

1.0

D;.;.;.;.

Vest4

0.92

MutPred

0.48

Loss of MoRF binding (P = 0.0069);Loss of MoRF binding (P = 0.0069);Loss of MoRF binding (P = 0.0069);Loss of MoRF binding (P = 0.0069);Loss of MoRF binding (P = 0.0069);

MVP

0.99

MPC

0.0040

ClinPred

0.92

GERP RS

5.6

Varity_R

0.49

gMVP

0.88

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over