7-117531107-A-G

Position:

• chr7-117531107-A-G

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000492.4(CFTR):​c.482A>G​(p.Tyr161Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,458,630 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging 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. Y161D) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CFTR NM_000492.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2 O:1
• Conservation: PhyloP100: 8.87

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 Pathogenic. Variant got 10 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
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-117531106-T-G is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CFTR	NM_000492.4	c.482A>G	p.Tyr161Cys	missense_variant	4/27	ENST00000003084.11	NP_000483.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.482A>G	p.Tyr161Cys	missense_variant	4/27	1	NM_000492.4	ENSP00000003084.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000404 AC: 1 AN: 247592 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 133646

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000547

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1458630 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 725610

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cystic fibrosis Uncertain:1 Other:1

not provided, no classification provided	literature only	ClinVar Staff, National Center for Biotechnology Information (NCBI)	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Nov 09, 2023	The p.Y161C variant (also known as c.482A>G), located in coding exon 4 of the CFTR gene, results from an A to G substitution at nucleotide position 482. The tyrosine at codon 161 is replaced by cysteine, an amino acid with highly dissimilar properties. This variant was identified in one individual with intermediate sweat chloride levels in conjunction with p.F508del; however, phase and detailed clinical information was not provided (Hirtz S et al. Gastroenterology, 2004 Oct;127:1085-95). It was also identified in a male with congenital bilateral absence of the vas deferens in conjunction with p.D1352H; however, phase information was not provided (Yuan P et al. Andrology, 2019 May;7:329-340). In a rectal biopsy of an individual with p.Y161C and p.F508del, residual chloride secretion was 37% compared to wild type (Hirtz S et al. Gastroenterology, 2004 Oct;127:1085-95; Roth EK et al. PLoS One, 2011 Aug;6:e24445). 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. -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Jul 28, 2023

Variant summary: CFTR c.482A>G (p.Tyr161Cys) results in a non-conservative amino acid change located in the transmembrane domain (IPR011527) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 247592 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.482A>G has been reported in the literature as a compound heterozygous genotype in an individual with CBAVD (Yuan_2019), and together with F508del in an individual diagnosed with Cystic Fibrosis, but who had indeterminate sweat chloride levels (44 mmol/L) and who had residual channel function (25-37% of normal controls) determined in native rectal epithelia (Hirtz_2004). These reports do not provide unequivocal conclusions about association of the variant with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 15480987, 30811104). No submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. 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	Pathogenic	0.80
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.48
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.93	D;.;.;D;.
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;D;D;D
M_CAP	Pathogenic	0.86	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Pathogenic	3.0	M;.;.;.;M
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-7.9	D;.;.;D;.
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;.;.;D;.
Sift4G	Pathogenic	0.0	D;.;.;D;.
Polyphen		1.0	D;.;.;.;.
Vest4		0.98
MutPred		0.90		Gain of methylation at K162 (P = 0.0148);Gain of methylation at K162 (P = 0.0148);Gain of methylation at K162 (P = 0.0148);Gain of methylation at K162 (P = 0.0148);Gain of methylation at K162 (P = 0.0148);
MVP		1.0
MPC		0.015
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.96
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		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: rs397508730; hg19: chr7-117171161;