chr7-117591993-A-T

Variant names:

• chr7-117591993-A-T
• rs397508310
• NM_000492.4:c.1826A>T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP3_Strong PP5

The NM_000492.4(CFTR):​c.1826A>T​(p.His609Leu) 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H609R) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CFTR NM_000492.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:2
• Conservation: PhyloP100: 8.60

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 11 ACMG points.

• PM1: In a domain ABC transporter 1 (size 223) in uniprot entity CFTR_HUMAN there are 54 pathogenic changes around while only 9 benign (86%) 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 chr7-117591993-A-G is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.959
• PP5: Variant 7-117591993-A-T is Pathogenic according to our data. Variant chr7-117591993-A-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 53399.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Likely_pathogenic=3}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CFTR	NM_000492.4	c.1826A>T	p.His609Leu	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.1826A>T	p.His609Leu	missense_variant	Exon 14 of 27	1	NM_000492.4	ENSP00000003084.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Cystic fibrosis Pathogenic:1 Uncertain:2

Oct 18, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. This variant disrupts the p.His609 amino acid residue in CFTR. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 16189704, 19457724). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. ClinVar contains an entry for this variant (Variation ID: 53399). This missense change has been observed in individual(s) with clinical features of CFTR-related conditions (PMID: 21520337, 25910067, 31005549). This variant is not present in population databases (ExAC no frequency). This sequence change replaces histidine with leucine at codon 609 of the CFTR protein (p.His609Leu). The histidine residue is moderately conserved and there is a moderate physicochemical difference between histidine and leucine. -

Jul 22, 2021

Genome-Nilou Lab

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 28, 2017

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The CFTR c.1826A>T (p.His609Leu) variant is a missense variant that has been reported in a compound heterozygous state with an intronic variant in one individual with congenital bilateral absence of the vas deferens (CBAVD) (Steiner et al. 2011). The p.His609Leu variant was absent from 319 controls. This variant is not found in the 1000 Genomes Project, the Exome Sequencing Project, or the Exome Aggregation Consortium despite being found in a region of good sequencing coverage. Therefore, it is presumed to be rare. Based on the limited evidence, the p.His609Leu variant is classified as a variant of unknown significance but suspicious for pathogenicity for CFTR-related disorders. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -

not provided Pathogenic:2

Dec 27, 2016

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 15, 2023

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.24
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Uncertain	24
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.73	D;.;T;.
Eigen	Uncertain	0.37
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;D;D
M_CAP	Pathogenic	0.63	D
MetaRNN	Pathogenic	0.96	D;D;D;D
MetaSVM	Uncertain	0.19	D
MutationAssessor	Benign	-0.36	N;.;.;.
PrimateAI	Pathogenic	0.80	T
PROVEAN	Uncertain	-2.4	N;.;N;.
REVEL	Pathogenic	0.75
Sift	Benign	0.49	T;.;T;.
Sift4G	Uncertain	0.011	D;.;D;.
Polyphen		0.99	D;.;.;.
Vest4		0.83
MutPred		0.91		Loss of disorder (P = 0.052);.;.;.;
MVP		0.97
MPC		0.0038
ClinPred		0.90	D
GERP RS		5.5
Varity_R		0.71
gMVP		0.94

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs397508310; hg19: chr7-117232047; COSMIC: COSV50068019; COSMIC: COSV50068019;