rs201759207
Variant summary
Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM1PP2
The NM_000492.4(CFTR):c.2770G>A(p.Asp924Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000141 in 1,613,916 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. D924H) has been classified as Uncertain significance.
Frequency
Consequence
NM_000492.4 missense
Scores
Clinical Significance
Conservation
Publications
- cystic fibrosisInheritance: 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 deferensInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- hereditary chronic pancreatitisInheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
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ACMG classification
Our verdict: Uncertain_significance. The variant received 3 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| CFTR | NM_000492.4 | c.2770G>A | p.Asp924Asn | missense_variant | Exon 17 of 27 | ENST00000003084.11 | NP_000483.3 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000151 AC: 23AN: 152164Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.0000676 AC: 17AN: 251412 AF XY: 0.0000810 show subpopulations
GnomAD4 exome AF: 0.000140 AC: 204AN: 1461752Hom.: 0 Cov.: 32 AF XY: 0.000143 AC XY: 104AN XY: 727184 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000151 AC: 23AN: 152164Hom.: 0 Cov.: 33 AF XY: 0.000135 AC XY: 10AN XY: 74326 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Cystic fibrosis Pathogenic:1Uncertain:4Other:1
The p.D924N variant (also known as c.2770G>A), located in coding exon 17 of the CFTR gene, results from a G to A substitution at nucleotide position 2770. The aspartic acid at codon 924 is replaced by asparagine, an amino acid with highly similar properties. This variant was detected in two individuals diagnosed with cystic fibrosis; however, additional genotype and phenotype information was not provided (Alonso MJ et al. Ann. Hum. Genet., 2007 Mar;71:194-201; Zitkiewicz E et al. PLoS ONE, 2014 Feb;9:e89094). In one French individual, the p.D924N variant was reported in cis with p.F508del (Baatallah N et al. Hum. Mutat., 2018 Apr;39:506-514). This variant was also identified in trans with a 5T variant in an individual with recurrent pancreatitis (Koyano S et al. Pancreas, 2010 Jul;39:686-7). This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on available evidence to date, the clinical significance of this alteration remains unclear. -
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This sequence change replaces aspartic acid, which is acidic and polar, with asparagine, which is neutral and polar, at codon 924 of the CFTR protein (p.Asp924Asn). This variant is present in population databases (rs201759207, gnomAD 0.01%). This missense change has been observed in individual(s) with CFTR-related conditions (PMID: 20562583). ClinVar contains an entry for this variant (Variation ID: 53565). 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 with a positive predictive value of 80%. 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 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. -
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This variant was identified in 1 patient with a clinically confirmed diagnosis of cystic fibrosis. The variant was classified in the context of a project re-classifying variants in the German Cystic Fibrosis Registry (Muko.e.V.). Link: https://www.muko.info/angebote/qualitaetsmanagement/register/cf-einrichtungen/mukoweb. Criteria applied: PM3_STR, PM2_SUP, PM5_SUP, PP3, PS3_SUP, PP4 -
not provided Uncertain:6
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The CFTR c.2770G>A; p.Asp924Asn variant (rs201759207) has been reported in cystic fibrosis patients, but its clinical significance was not determined (Alonso 2006, Zietkiewicz 2014). It is listed in ClinVar (Variation ID: 53565) and observed in the general population at an overall frequency of 0.009% (25/277152 alleles) in the Genome Aggregation Database. The aspartic acid at codon 924 is highly conserved, but computational algorithms (PolyPhen-2: probably damaging; SIFT: tolerated) are inconclusive on the variant's impact on the protein. Due to the limited information regarding this variant, its clinical significance cannot be determined with certainty. References: Alonso M et al. Spectrum of mutations in the CFTR gene in cystic fibrosis patients of Spanish ancestry. Ann Hum Genet. 2007; 71(Pt 2):194-201. Zietkiewicz E et al. CFTR mutations spectrum and the efficiency of molecular diagnostics in Polish cystic fibrosis patients. PLoS One. 2014; 9(2):e89094. -
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not specified Uncertain:1
Variant summary: CFTR c.2770G>A (p.Asp924Asn) results in a conservative amino acid change located in the ABC transporter type 1, transmembrane domain (IPR011527) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. Consensus agreement among computation tools predict no significant impact on normal splicing. In a minigene assay this variant has been shown to cause exon skipping (Baatallah_2018), however, the exact in-vivo consequences of this finding are not known. The authors speculated that this variant when present in cis with p.Phe508del could result in a reduced amount of full length CFTR, hence reducing the amount of CFTR-p.Phe508del targeted by corrector/potentiator treatment. The variant allele was found at a frequency of 6.8e-05 in 251412 control chromosomes (gnomAD). c.2770G>A has been reported in the literature in individuals affected with Cystic Fibrosis (CF), CF- related disorders as well as pancreatic cancer (e.g. Alonso_2007, deCid_2010, Koyano_2010, Zietkiewicz_2013, Guan_2018, Tamura_2019, Claustres_2017). These reports however, do not provide unequivocal conclusions about association of the variant with Cystic Fibrosis. CFTR2 database also report this variant as variant of uncertain significance. Co-occurrences with other pathogenic variant(s) have been reported (Baatallah_2018, CFTR c.1521_1523del, p.F508del), providing supporting evidence for a benign role. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect resulted in approximately 33% of normal chloride channel conductance relative to wild type (Bihler_2024). The following publications have been ascertained in the context of this evaluation (PMID: 19812525, 17331079, 24586523, 25735457, 20562583, 28603918, 29997923, 29669919, 31883651, 29271547, 38388235). ClinVar contains an entry for this variant (Variation ID: 53565). Based on the evidence outlined above, the variant was classified as uncertain significance. -
CFTR-related disorder Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at