NM_000492.4:c.325T>A

Variant names:

• chr7-117530950-T-A
• rs397508522
• NM_000492.4:c.325T>A

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5

The NM_000492.4(CFTR):​c.325T>A​(p.Tyr109Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,516 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. Y109C) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CFTR NM_000492.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:2
• Conservation: PhyloP100: 7.61
• Publications: 5 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: Pathogenic. The variant received 12 ACMG points.

• PM1: In a hotspot region, there are 18 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 17 uncertain 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 chr7-117530951-A-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 7197.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.985
• PP5: Variant 7-117530950-T-A is Pathogenic according to our data. Variant chr7-117530950-T-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 53695.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CFTR	NM_000492.4	c.325T>A	p.Tyr109Asn	missense_variant	Exon 4 of 27	ENST00000003084.11	NP_000483.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.325T>A	p.Tyr109Asn	missense_variant	Exon 4 of 27	1	NM_000492.4	ENSP00000003084.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251124 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461516 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727056

African (AFR) AF: 0.00 AC: 0 AN: 33462

American (AMR) AF: 0.00 AC: 0 AN: 44658

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26122

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.00 AC: 0 AN: 86242

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53400

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5738

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111826

Other (OTH) AF: 0.00 AC: 0 AN: 60380

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:2 Uncertain:2

Aug 16, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Y109N variant (also known as c.325T>A), located in coding exon 4 of the CFTR gene, results from a T to A substitution at nucleotide position 325. The tyrosine at codon 109 is replaced by asparagine, an amino acid with dissimilar properties. This alteration has been identified in individuals with a clinical diagnosis of cystic fibrosis (Rodman DM et al. Am J Respir Crit Care Med, 2005 Mar;171:621-6; Abou Alaiwa MH et al. J Cyst Fibros, 2014 Jul;13:373-7). This amino acid position is well 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. -

Nov 14, 2024

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

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: CFTR c.325T>A (p.Tyr109Asn) results in a non-conservative amino acid change located in the ABC transporter type 1, transmembrane domain 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 251124 control chromosomes. c.325T>A has been reported in the literature in individuals affected with Cystic Fibrosis, including at least one patient who had a late diagnosis and an individual with intermmediate sweat chloride levels (e.g. Dragomir_2001, Schaedel_2002, Rodman_2005, Abou Alaiwa_2014, Raraigh_2022). A different variant affecting the same codon has been classified as pathogenic by our lab (c.326A>G, p.Tyr109Cys), supporting the critical relevance of codon 109 to CFTR protein function. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect resulted in approximately (Gt channel conductance) 4% of normal chloride channel conductance relative to wild type (e.g., Bihler_2024). The following publications have been ascertained in the context of this evaluation (PMID: 24418186, 38388235, 11555145, 34782259, 15591474, 12001283). ClinVar contains an entry for this variant (Variation ID: 53695). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Jan 23, 2018

Counsyl

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Nov 29, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Tyr109 amino acid residue in CFTR. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 32539862). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt CFTR protein function. ClinVar contains an entry for this variant (Variation ID: 53695). This missense change has been observed in individuals with cystic fibrosis (PMID: 11555145, 15591474). This variant is present in population databases (rs397508522, gnomAD 0.0009%). This sequence change replaces tyrosine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 109 of the CFTR protein (p.Tyr109Asn). -

Cystic fibrosis;C0238339:Hereditary pancreatitis;C0403814:Congenital bilateral aplasia of vas deferens from CFTR mutation;C2749757:Bronchiectasis with or without elevated sweat chloride 1 Pathogenic:1

Apr 07, 2024

Fulgent Genetics, Fulgent Genetics

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	Pathogenic	0.86
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.87	.;D;.;.;T;.
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.97	D;D;D;D;D;D
M_CAP	Pathogenic	0.84	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.2	.;M;.;.;.;M
PhyloP100		7.6
PrimateAI	Uncertain	0.77	T
PROVEAN	Pathogenic	-8.1	D;D;.;.;D;.
REVEL	Pathogenic	0.92
Sift	Pathogenic	0.0	D;D;.;.;D;.
Sift4G	Pathogenic	0.0	D;D;.;.;D;.
Polyphen		1.0	.;D;.;.;.;.
Vest4		0.96
MutPred		0.92		.;Gain of disorder (P = 0.0141);Gain of disorder (P = 0.0141);Gain of disorder (P = 0.0141);Gain of disorder (P = 0.0141);Gain of disorder (P = 0.0141);
MVP		1.0
MPC		0.011
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.94
gMVP		0.96
Mutation Taster		=6/94	disease causing

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

Other links and lift over

dbSNP: rs397508522; hg19: chr7-117171004;