rs397508751

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM1BP4_StrongBS2_Supporting

The NM_000492.4(CFTR):​c.547C>A​(p.Leu183Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00017 in 1,602,238 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00018 ( 2 hom. )

Consequence

CFTR
NM_000492.4 missense

Scores

6
8
5

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8B:1O:1

Conservation

PhyloP100: 3.52
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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

PM1
In a domain ABC transmembrane type-1 1 (size 284) in uniprot entity CFTR_HUMAN there are 65 pathogenic changes around while only 10 benign (87%) in NM_000492.4
BP4
Computational evidence support a benign effect (MetaRNN=0.02408579).
BS2
High Homozygotes in GnomAdExome4 at 2 AR geneVariant has number of homozygotes lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CFTRNM_000492.4 linkc.547C>A p.Leu183Ile missense_variant Exon 5 of 27 ENST00000003084.11 NP_000483.3 P13569-1A0A024R730

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
CFTRENST00000003084.11 linkc.547C>A p.Leu183Ile missense_variant Exon 5 of 27 1 NM_000492.4 ENSP00000003084.6 P13569-1

Frequencies

GnomAD3 genomes
AF:
0.000105
AC:
16
AN:
152156
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00331
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.000299
AC:
75
AN:
250676
Hom.:
0
AF XY:
0.000369
AC XY:
50
AN XY:
135546
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:
0.00242
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.000164
GnomAD4 exome
AF:
0.000177
AC:
256
AN:
1449966
Hom.:
2
Cov.:
26
AF XY:
0.000260
AC XY:
188
AN XY:
722146
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:
0.00276
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.00
Gnomad4 OTH exome
AF:
0.000317
GnomAD4 genome
AF:
0.000105
AC:
16
AN:
152272
Hom.:
0
Cov.:
32
AF XY:
0.000134
AC XY:
10
AN XY:
74458
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.00
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00331
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.00
Gnomad4 OTH
AF:
0.00
Bravo
AF:
0.0000227
ExAC
AF:
0.000371
AC:
45
Asia WGS
AF:
0.00144
AC:
6
AN:
3478

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:8Benign:1Other:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Cystic fibrosis Uncertain:3Benign:1Other:1
Mar 22, 2023
Ambry Genetics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

The p.L183I variant (also known as c.547C>A), located in coding exon 5 of the CFTR gene, results from a C to A substitution at nucleotide position 547. The leucine at codon 183 is replaced by isoleucine, an amino acid with highly similar properties. This variant was identified in an individual with lower respiratory tract infections, sinusitis, failure to thrive and elevated sweat chloride levels of 57 and 60; a second CFTR alteration was not identified (Shastri SS et al. J. Cyst. Fibros., 2008 Mar;7:110-5). It was also identified in a 28-year-old male with normal sweat chloride levels, bronchiectasis, and pulmonary non-tuberculosis mycobacterial infection; a second CFTR alteration was not identified (Ziedalski TM et al. Chest, 2006 Oct;130:995-1002). An in vitro study attempting to identify exonic alterations which weaken core splicing motifs using hybrid minigene constructs revealed a increased basal exon skipping of exon 5 with this particular nucleotide substitution compared to the wild type construct (Aissat A et al. Hum. Mutat., 2013 Jun;34:873-81). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on available evidence to date, the clinical significance of this alteration remains unclear. -

Jul 22, 2021
Genome-Nilou Lab
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

-
ClinVar Staff, National Center for Biotechnology Information (NCBI)
Significance: not provided
Review Status: no classification provided
Collection Method: literature only

- -

Mar 01, 2023
Neuberg Centre For Genomic Medicine, NCGM
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

The missense variant c.547C>A(p.Leu183Ile) in the CFTR gene has been reported previously in a heterozygous state in individuals affected with asthma and chronic pancreatitis. An in vitro study attempting to identify exonic alterations which weaken core splicing motifs using hybrid minigene constructs revealed an increased basal exon skipping of exon 5 with this particular nucleotide substitution compared to the wild-type construct (Muthuswamy et al., 2014; Aissat et al., 2013). This variant is reported with the allele frequency (0.02%) in the gnomAD Exomes and novel (not in any individuals) in 1000 Genomes. This variant has been reported to the ClinVar database as Uncertain Significance/ Likely Benign. The amino acid Leucine at position 183 is changed to a Isoleucine changing protein sequence and it might alter its composition and physico- chemical properties. The variant is predicted as damaging by SIFT. The amino acid change p.Leu183Ile in CFTR is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. Based on available evidence to date, the clinical significance of this alteration remains unclear. For these reasons, this variant has been classified as Uncertain Significance. -

Dec 24, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

not provided Uncertain:3
-
Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen
Significance: Uncertain significance
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

Jun 30, 2021
Mayo Clinic Laboratories, Mayo Clinic
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

-
Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center
Significance: Uncertain significance
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

not specified Uncertain:1
Sep 11, 2020
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.547C>A (p.Leu183Ile) results in a conservative amino acid change located in the ABC transporter type 1, transmembrane domain (IPR011527) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.0003 in 250676 control chromosomes (gnomAD). This frequency is not significantly higher than expected for a pathogenic variant in CFTR causing Cystic Fibrosis (0.0003 vs 0.013), allowing no conclusion about variant significance. c.547C>A has been reported in the literature in individuals affected with Cystic Fibrosis or CFTR related disorders (Ziedalski_2006, Shastri_2008). These reports do not provide unequivocal conclusions about association of the variant with Cystic Fibrosis. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported, although one study showed this variant did not lead to exon skipping (Aissat_2013). One ClinVar submitter (evaluation after 2014) cites the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

CFTR-related disorder Uncertain:1
Apr 10, 2024
PreventionGenetics, part of Exact Sciences
Significance: Uncertain significance
Review Status: no assertion criteria provided
Collection Method: clinical testing

The CFTR c.547C>A variant is predicted to result in the amino acid substitution p.Leu183Ile. This variant has been reported in a single patient with cystic fibrosis (in the absence of a second pathogenic variant) and another patient with CF-related symptoms (with normal sweat chloride levels) (Ziedalski et al 2006. PubMed ID: 17035430 and Shastri et al. 2008. PubMed ID: 17716958, respectively). In a hybrid minigene assay, the c.547C>A variant increased exon skipping by ~10% compared to wild-type cells in vitro (Aissat et al 2013. PubMed ID: 23420618). However, it is not clear whether this is sufficient to cause disease. This variant is reported in 0.24% of alleles in individuals of South Asian descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.25
BayesDel_addAF
Benign
-0.064
T
BayesDel_noAF
Uncertain
0.13
CADD
Pathogenic
26
DANN
Uncertain
0.99
DEOGEN2
Uncertain
0.69
D;.;.;.
Eigen
Pathogenic
0.76
Eigen_PC
Pathogenic
0.73
FATHMM_MKL
Uncertain
0.96
D
LIST_S2
Uncertain
0.95
D;D;D;D
M_CAP
Pathogenic
0.75
D
MetaRNN
Benign
0.024
T;T;T;T
MetaSVM
Pathogenic
0.85
D
MutationAssessor
Uncertain
2.6
M;.;.;M
PrimateAI
Pathogenic
0.85
D
PROVEAN
Benign
-1.3
N;.;.;.
REVEL
Uncertain
0.63
Sift
Uncertain
0.019
D;.;.;.
Sift4G
Pathogenic
0.0
D;.;.;.
Polyphen
1.0
D;.;.;.
Vest4
0.68
MutPred
0.63
Gain of catalytic residue at L188 (P = 0.0985);Gain of catalytic residue at L188 (P = 0.0985);Gain of catalytic residue at L188 (P = 0.0985);Gain of catalytic residue at L188 (P = 0.0985);
MVP
1.0
MPC
0.015
ClinPred
0.12
T
GERP RS
5.5
Varity_R
0.75
gMVP
0.83

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.030
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.

Other links and lift over

dbSNP: rs397508751; hg19: chr7-117174387; API