rs1043006335

chr7-117606739-T-Cchr7-117606739-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000492.4(CFTR):c.2974T>C(p.Phe992Leu) 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 nucleotide change resulting in same amino acid change has been previously reported as Uncertain significancein ClinVar.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CFTR NM_000492.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.40

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]

(HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a domain ABC transmembrane type-1 2 (size 296) in uniprot entity CFTR_HUMAN there are 141 pathogenic changes around while only 14 benign (91%) in NM_000492.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.86

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CFTR	NM_000492.4	c.2974T>C	p.Phe992Leu	missense_variant	18/27	ENST00000003084.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CFTR	ENST00000003084.11	c.2974T>C	p.Phe992Leu	missense_variant	18/27	1	NM_000492.4	P2
	ENST00000456270.1	n.178-1750A>G		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 26

GnomAD4 genome Cov.: 32

Asia WGS AF: 0.000577 AC: 2 AN: 3478

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

Invitae

May 29, 2018

This sequence change replaces phenylalanine with leucine at codon 992 of the CFTR protein (p.Phe992Leu). The phenylalanine residue is highly conserved and there is a small physicochemical difference between phenylalanine and leucine. 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. 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 tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
Cadd	Pathogenic	27
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.58	D;.;.;T;.
Eigen	Uncertain	0.51
Eigen_PC	Uncertain	0.55
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.78	T;T;T;T;T
M_CAP	Pathogenic	0.52	D
MetaRNN	Pathogenic	0.86	D;D;D;D;D
MetaSVM	Uncertain	0.20	D
MutationAssessor	Benign	1.2	L;.;.;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.69	T
PROVEAN	Benign	-1.7	N;.;.;N;.
REVEL	Pathogenic	0.81
Sift	Benign	0.062	T;.;.;T;.
Sift4G	Pathogenic	0.0	D;.;.;D;.
Polyphen		1.0	D;.;.;.;.
Vest4		0.86
MutPred		0.69		Loss of stability (P = 0.0978);.;.;.;.;
MVP		1.0
MPC		0.0048
ClinPred		0.92	D
GERP RS		5.4
Varity_R		0.84
gMVP		0.92

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: rs1043006335; hg19: chr7-117246793;