rs35516286

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1PM2PP3_ModeratePP5

The NM_000492.4(CFTR):​c.443T>A​(p.Ile148Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,594 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I148T) has been classified as Benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

CFTR
NM_000492.4 missense

Scores

5
11
3

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4U:4O:1

Conservation

PhyloP100: 7.61
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_pathogenic. Variant got 7 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
PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.896
PP5
Variant 7-117531068-T-A is Pathogenic according to our data. Variant chr7-117531068-T-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 53949.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Uncertain_significance=4, Pathogenic=2, not_provided=1}.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CFTRNM_000492.4 linkc.443T>A p.Ile148Asn missense_variant Exon 4 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.443T>A p.Ile148Asn missense_variant Exon 4 of 27 1 NM_000492.4 ENSP00000003084.6 P13569-1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152140
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000655
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD4 exome
AF:
0.00000274
AC:
4
AN:
1461454
Hom.:
0
Cov.:
31
AF XY:
0.00000550
AC XY:
4
AN XY:
727004
show subpopulations
Gnomad4 AFR exome
AF:
0.0000299
Gnomad4 AMR exome
AF:
0.0000224
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:
8.99e-7
Gnomad4 OTH exome
AF:
0.0000166
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152140
Hom.:
0
Cov.:
32
AF XY:
0.0000135
AC XY:
1
AN XY:
74310
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.0000655
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.00
Gnomad4 OTH
AF:
0.00
Bravo
AF:
0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:4Uncertain:4Other:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Cystic fibrosis Pathogenic:2Uncertain:3Other:1
Jul 22, 2021
Genome-Nilou Lab
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Nov 23, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with asparagine, which is neutral and polar, at codon 148 of the CFTR protein (p.Ile148Asn). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with atypical cystic fibrosis and cystic fibrosis (PMID: 15480987, 26898888, 28771972). ClinVar contains an entry for this variant (Variation ID: 53949). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt CFTR protein function with a positive predictive value of 80%. 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. -

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

- -

Aug 08, 2024
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Variant summary: CFTR c.443T>A (p.Ile148Asn) results in a non-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 was absent in 250526 control chromosomes. c.443T>A has been reported in the literature in the presumed compound heterozygous state in multiple individuals affected with Cystic Fibrosis or atypical Cystic Fibrosis (example, Hirtz_2004, Silva_2016,_Silva_2020, Maciel_2020). These data indicate that the variant is likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect resulted in approximately 5.75% of normal chloride channel conductance relative to wild type (e.g., Bihler_2024). The following publications have been ascertained in the context of this evaluation (PMID: 38388235, 32084388, 33111836, 11504857, 15480987, 10571949, 28771972, 25735457, 33424627, 26898888, 32819855, 26429520). ClinVar contains an entry for this variant (Variation ID: 53949). Based on the evidence outlined above, the variant was classified as pathogenic. -

Sep 14, 2020
Mendelics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Sep 13, 2024
Ambry Genetics
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

The p.I148N pathogenic mutation (also known as c.443T>A), located in coding exon 4 of the CFTR gene, results from a T to A substitution at nucleotide position 443. The isoleucine at codon 148 is replaced by asparagine, an amino acid with dissimilar properties. The variant has been reported to occur in cis with 5T (Silva A et al. Rev Port Pneumol (2006), 2016 Feb;22:141-5; Nunes LM et al. Pediatr Pulmonol, 2017 Oct;52:1300-1305). p.I148N in isolation or in cis with 5T has been identified in conjunction with other CFTR variant(s) in individuals with features consistent with cystic fibrosis (Hirtz S et al. Gastroenterology, 2004 Oct;127:1085-95; Silva A et al. Rev Port Pneumol (2006), 2016 Feb;22:141-5; Nunes LM et al. Pediatr Pulmonol, 2017 Oct;52:1300-1305' Maciel LMZ et al. Cad Saude Publica, 2020 Oct;36:e00049719; Ambry internal data). In an assay testing CFTR function, this variant showed a functionally abnormal result (Bihler H et al. J Cyst Fibros, 2024 Jul;23:664-675). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the supporting evidence, this variant is interpreted as a disease-causing mutation. -

Cystic fibrosis;C0403814:Congenital bilateral aplasia of vas deferens from CFTR mutation Pathogenic:1
-
Baylor Genetics
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Bronchiectasis with or without elevated sweat chloride 1 Pathogenic:1
Mar 02, 2024
Baylor Genetics
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

not provided Uncertain:1
Feb 27, 2017
Eurofins Ntd Llc (ga)
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.50
BayesDel_addAF
Pathogenic
0.23
D
BayesDel_noAF
Uncertain
0.090
CADD
Uncertain
24
DANN
Uncertain
0.99
DEOGEN2
Uncertain
0.79
D;.;.;T;.
Eigen
Benign
0.11
Eigen_PC
Uncertain
0.30
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Uncertain
0.97
D;D;D;D;D
M_CAP
Pathogenic
0.57
D
MetaRNN
Pathogenic
0.90
D;D;D;D;D
MetaSVM
Uncertain
0.087
D
MutationAssessor
Benign
1.4
L;.;.;.;L
PrimateAI
Uncertain
0.51
T
PROVEAN
Uncertain
-2.8
D;.;.;D;.
REVEL
Uncertain
0.63
Sift
Uncertain
0.0020
D;.;.;D;.
Sift4G
Pathogenic
0.0010
D;.;.;D;.
Polyphen
0.031
B;.;.;.;.
Vest4
0.98
MutPred
0.85
Loss of stability (P = 0.092);Loss of stability (P = 0.092);Loss of stability (P = 0.092);Loss of stability (P = 0.092);Loss of stability (P = 0.092);
MVP
1.0
MPC
0.0036
ClinPred
0.96
D
GERP RS
5.7
Varity_R
0.86
gMVP
0.97

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.

Other links and lift over

dbSNP: rs35516286; hg19: chr7-117171122; API