rs757165481

Positions:

• chr7-117594984-T-A
• chr7-117594984-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The ENST00000003084.11(CFTR):​c.2545T>A​(p.Tyr849Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y849C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CFTR ENST00000003084.11 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.25

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.962

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CFTR	NM_000492.4	c.2545T>A	p.Tyr849Asn	missense_variant	15/27	ENST00000003084.11	NP_000483.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.2545T>A	p.Tyr849Asn	missense_variant	15/27	1	NM_000492.4	ENSP00000003084	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cystic fibrosis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 17, 2018

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This sequence change replaces tyrosine with asparagine at codon 849 of the CFTR protein (p.Tyr849Asn). The tyrosine residue is highly conserved and there is a large physicochemical difference between tyrosine and asparagine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with CFTR-related disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.82
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.47
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.96	D;.;D;.
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D;D
M_CAP	Pathogenic	0.81	D
MetaRNN	Pathogenic	0.96	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.4	M;.;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.69	T
PROVEAN	Pathogenic	-6.1	D;.;D;.
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;.;D;.
Sift4G	Pathogenic	0.0	D;.;D;.
Polyphen		1.0	D;.;.;.
Vest4		0.96
MutPred		0.78		Loss of sheet (P = 0.0063);.;.;.;
MVP		1.0
MPC		0.013
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.92
gMVP		0.84

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

Other links and lift over

dbSNP: rs757165481; hg19: chr7-117235038;