7-117592566-C-T

Variant names:

• chr7-117592566-C-T
• rs397508373
• NM_000492.4:c.2399C>T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_000492.4(CFTR):​c.2399C>T​(p.Ala800Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000073 in 1,370,008 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign 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. A800G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.3e-7 (0 hom.)
• Consequence: CFTR NM_000492.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.76
• Publications: 7 publications found

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]

CFTR Gene-Disease associations (from GenCC):

• cystic fibrosis

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, Orphanet
• congenital bilateral absence of vas deferens

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary chronic pancreatitis

  Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 197 curated pathogenic missense variants (we use a threshold of 10). The gene has 46 curated benign missense variants. Gene score misZ: -3.1397 (below the threshold of 3.09). Trascript score misZ: -1.0868 (below the threshold of 3.09). GenCC associations: The gene is linked to hereditary chronic pancreatitis, cystic fibrosis, congenital bilateral absence of vas deferens.
• BP4: Computational evidence support a benign effect (MetaRNN=0.119960636).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CFTR	NM_000492.4	c.2399C>T	p.Ala800Val	missense_variant	Exon 14 of 27	ENST00000003084.11	NP_000483.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.2399C>T	p.Ala800Val	missense_variant	Exon 14 of 27	1	NM_000492.4	ENSP00000003084.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000555 AC: 1 AN: 180258 AF XY: 0.0000105

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000631

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 7.30e-7 AC: 1 AN: 1370008 Hom.: 0 Cov.: 31 AF XY: 0.00000149 AC XY: 1 AN XY: 672408

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 30356

American (AMR) AF: 0.00 AC: 0 AN: 29208

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 20228

East Asian (EAS) AF: 0.0000257 AC: 1 AN: 38976

South Asian (SAS) AF: 0.00 AC: 0 AN: 69198

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49990

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5322

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1070298

Other (OTH) AF: 0.00 AC: 0 AN: 56432

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cystic fibrosis Uncertain:1

Aug 17, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine with valine at codon 800 of the CFTR protein (p.Ala800Val). The alanine residue is weakly conserved and there is a small physicochemical difference between alanine and valine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with CFTR-related conditions. 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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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	Benign	0.091
BayesDel_addAF	Benign	-0.037	T
BayesDel_noAF	Benign	-0.11
CADD	Benign	19
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.59	D;.;T;.
Eigen	Benign	-0.73
Eigen_PC	Benign	-0.70
FATHMM_MKL	Benign	0.35	N
LIST_S2	Uncertain	0.94	D;D;D;D
M_CAP	Benign	0.064	D
MetaRNN	Benign	0.12	T;T;T;T
MetaSVM	Uncertain	-0.21	T
MutationAssessor	Benign	0.69	N;.;.;.
PhyloP100		1.8
PrimateAI	Benign	0.24	T
PROVEAN	Benign	-0.60	N;.;N;.
REVEL	Benign	0.26
Sift	Benign	0.20	T;.;T;.
Sift4G	Uncertain	0.050	T;.;D;.
Polyphen		0.013	B;.;.;.
Vest4		0.28
MutPred		0.39		Loss of relative solvent accessibility (P = 0.0186);.;.;.;
MVP		0.98
MPC		0.0041
ClinPred		0.063	T
GERP RS		3.4
Varity_R		0.029
gMVP		0.45
Mutation Taster		=31/69	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs397508373; hg19: chr7-117232620;