chr7-117530918-A-G
Variant summary
Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1PM2PP3_StrongPP5_Very_Strong
The NM_000492.4(CFTR):c.293A>G(p.Gln98Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,612,730 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 Pathogenic (★★★).
Frequency
Consequence
NM_000492.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 16 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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CFTR | NM_000492.4 | c.293A>G | p.Gln98Arg | missense_variant | Exon 4 of 27 | ENST00000003084.11 | NP_000483.3 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152178Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.00000797 AC: 2AN: 251054Hom.: 0 AF XY: 0.00 AC XY: 0AN XY: 135670
GnomAD4 exome AF: 0.00000274 AC: 4AN: 1460552Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1AN XY: 726676
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152178Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74346
ClinVar
Submissions by phenotype
Cystic fibrosis Pathogenic:8
This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 98 of the CFTR protein (p.Gln98Arg). This variant is present in population databases (rs397508464, gnomAD 0.006%). This missense change has been observed in individual(s) with cystic fibrosis (PMID: 7581407, 16778407, 19652440). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 53606). 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%. Experimental studies have shown that this missense change affects CFTR function (PMID: 29805046). For these reasons, this variant has been classified as Pathogenic. -
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The p.Q98R pathogenic mutation (also known as c.293A>G), located in coding exon 4 of the CFTR gene, results from an A to G substitution at nucleotide position 293. The glutamine at codon 98 is replaced by arginine, an amino acid with highly similar properties. This mutation has been seen in individuals with elevated sweat chloride levels and pulmonary manifestations (Jung H et al. Korean J Lab Med, 2011 Jul;31:219-24). One study reported a homozygous individual with elevated sweat chloride levels and severe lung disease with allergic bronchopulmonary aspergillosis, but no gastrointestinal symptoms (Liu Y et al. Respirology, 2015 Feb;20:312-8). A functional study to assess the importance of the glutamine in this position suggests it may be involved in controlling the rate of chloride ion permeation through the pore (Ge N et al. J. Biol. Chem., 2004 Dec;279:55283-9). In addition, this mutation has been shown to decrease chloride channel activity compared to wild-type CFTR (Raraigh KS et al. Am. J. Hum. Genet., 2018 06;102:1062-1077). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Disease-causing CFTR variant. See www.CFTR2.org for phenotype information. -
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Variant summary: The CFTR c.293A>G (p.Gln98Arg) variant involves the alteration of a conserved nucleotide located in the ABC transporter type 1, transmembrane domain of the protein (InterPro). 4/5 in silico tools predict a damaging outcome for this variant. This variant was found in 2/119728 control chromosomes at a frequency of 0.0000167, which does not exceed the estimated maximal expected allele frequency of a pathogenic CFTR variant (0.0129603). This variant has been reported in numerous CF patients with diverse ethnicity background including Caucasians, African Americans, and Asians. The variant in these patients present both homozygously and compound heterozygously. Taken together, this variant is classified as pathogenic. -
not provided Pathogenic:2
The frequency of this variant in the general population, 0.000008 (2/251054 chromosomes, http://gnomad.broadinstitute.org), is consistent with pathogenicity. In the published literature, the variant has been reported in several compound heterozygotes affected with cystic fibrosis (UMD (http://www.umd.be/), PMIDs: 25580864 (2015), 23687349 (2013)). Additionally, functional studies showed reduced chloride channel activity indicating that this variant impacts protein function (PMID: 29805046 (2018)). Based on the available information, this variant is classified as pathogenic. -
PP3, PM2, PM3_very_strong, PS3 -
not specified Pathogenic:1
The CFTR c.293A>G; p.Gln98Arg variant (rs397508464) has been reported in multiple patients with cystic fibrosis (CF), either in trans to another pathogenic CFTR variant (Jung 2011, Koh 2005, Romey 1995) or in the homozygous state (Izumikawa 2009, Liu 2015). In testing performed at ARUP Laboratories, this variant has also been identified in multiple individuals with symptoms of CF who carry another pathogenic CFTR variant. Affected individuals with this variant can present with or without pancreatic insufficiency, although most are pancreatic-sufficient (CFTR2 database). The p.Gln98Arg variant is reported as pathogenic by multiple laboratories in ClinVar (Variation ID: 53606), and it is observed on only two chromosomes (2/251054 alleles) in the Genome Aggregation Database. The glutamine at residue 98 is highly conserved, it is located in the pore of the transmembrane channel of CFTR (Akabas 1994, Das 2017), and computational algorithms (PolyPhen-2, SIFT) predict that this variant is deleterious. Consistent with these predictions, the variant protein exhibits only 5.4% of wildtype chloride channel activity in a biochemical assay (Raraigh 2018). Based on available information, the p.Gln98Arg variant is considered to be pathogenic. References: CFTR2 database: https://cftr2.org/ Akabas M et al. Amino acid residues lining the chloride channel of the cystic fibrosis transmembrane conductance regulator. J Biol Chem. 1994; 269(21):14865-8. Das J et al. Transmembrane helical interactions in the CFTR channel pore. PLoS Comput Biol. 2017; 13(6):e1005594. Izumikawa K et al. Unique mutations of the cystic fibrosis transmembrane conductance regulator gene of three cases of cystic fibrosis in Nagasaki, Japan. Intern Med. 2009; 48(15):1327-31. Jung H et al. Heterogeneous spectrum of CFTR gene mutations in Korean patients with cystic fibrosis. Korean J Lab Med. 2011; 31(3):219-24. Koh W et al. Report of a Korean patient with cystic fibrosis, carrying Q98R and Q220X mutations in the CFTR gene. J Korean Med Sci. 2006; 21(3):563-6. Liu Y et al. Characterization of gene mutations and phenotypes of cystic fibrosis in Chinese patients. Respirology. 2015; 20(2):312-8. Raraigh KS et al. Functional Assays Are Essential for Interpretation of Missense Variants Associated with Variable Expressivity. Am J Hum Genet. 2018 Jun 7;102(6):1062-1077. Romey M et al. Novel missense mutation in the first transmembrane segment of the CFTR gene (Q98R) identified in a male adult. Hum Mutat. 1995; 6(2):190-1. -
CFTR-related disorder Pathogenic:1
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Cystic fibrosis;C0403814:Congenital bilateral aplasia of vas deferens from CFTR mutation Pathogenic:1
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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
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Bronchiectasis with or without elevated sweat chloride 1 Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at