7-117535326-C-T
Variant summary
Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong
The NM_000492.4(CFTR):c.658C>T(p.Gln220*) variant causes a stop gained change. The variant allele was found at a frequency of 0.0000123 in 1,461,828 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 (★★★). Variant results in nonsense mediated mRNA decay.
Frequency
Consequence
NM_000492.4 stop_gained
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: Pathogenic. The variant received 16 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt | 
|---|---|---|---|---|---|---|---|---|
| CFTR | NM_000492.4  | c.658C>T | p.Gln220* | stop_gained | Exon 6 of 27 | ENST00000003084.11 | NP_000483.3 | 
Ensembl
Frequencies
GnomAD3 genomes  Cov.: 32 
GnomAD2 exomes  AF:  0.00000398  AC: 1AN: 251438 AF XY:  0.00000736   show subpopulations 
GnomAD4 exome  AF:  0.0000123  AC: 18AN: 1461828Hom.:  0  Cov.: 32 AF XY:  0.0000138  AC XY: 10AN XY: 727216 show subpopulations 
Age Distribution
GnomAD4 genome  Cov.: 32 
ClinVar
Submissions by phenotype
Cystic fibrosis    Pathogenic:9 
This sequence change creates a premature translational stop signal (p.Gln220*) in the CFTR gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CFTR are known to be pathogenic (PMID: 1695717, 7691345, 9725922). This variant is present in population databases (rs397508778, gnomAD 0.0009%). This premature translational stop signal has been observed in individual(s) with clinical features of cystic fibrosis (PMID: 7515303, 16778407). 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: 54036). For these reasons, this variant has been classified as Pathogenic. -
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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. -
Disease-causing CFTR variant. See www.CFTR2.org for phenotype information. -
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Variant summary: CFTR c.658C>T (p.Gln220X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory (c.803delA, p.Asn268fsX17; c.850dupA, p.Met284fsX3; c.948delT, p.Phe316LeufsX12). The variant allele was found at a frequency of 4e-06 in 251438 control chromosomes (gnomAD). The variant, c.658C>T, has been reported in the literature in multiple individuals affected with Cystic Fibrosis (Koh_2006, Tomaiuolo_2010, Ooi_2012, Sosonay_2013). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. One publication, Sosnay_2013, reports that spliced RNA product is less than 10% of WT level predicted by NMD (nonsense mediated decay). Three ClinVar submissions including one expert panel (CFTR2) cite the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
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: PVS1, PM2_SUP, PM3_VSTR, PP4 -
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The p.Q220* pathogenic mutation (also known as c.658C>T), located in coding exon 6 of the CFTR gene, results from a C to T substitution at nucleotide position 658. This changes the amino acid from a glutamine to a stop codon within coding exon 6. This mutation was described in trans with a second pathogenic mutation in an individual presenting with respiratory symptoms, bronchiectasis, and elevated sweat chloride levels (Koh WJ et al. J Korean Med Sci. 2006;21(3):563-6). In addition to pulmonary symptoms and elevated sweat chloride levels, this mutation is also associated with pancreatic insufficiency (Sosnay PR et al. Nat Genet. 2013;45(10):1160-7). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -
Cystic fibrosis;C0403814:Congenital bilateral aplasia of vas deferens from CFTR mutation    Pathogenic:1 
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CFTR-related disorder    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