rs397508366
Variant summary
Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000492.4(CFTR):c.233dupT(p.Trp79LeufsTer32) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,612,054 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★★). Variant results in nonsense mediated mRNA decay.
Frequency
Consequence
NM_000492.4 frameshift
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 18 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
CFTR | NM_000492.4 | c.233dupT | p.Trp79LeufsTer32 | frameshift_variant | Exon 3 of 27 | ENST00000003084.11 | NP_000483.3 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152140Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.00000797 AC: 2AN: 250970Hom.: 0 AF XY: 0.00000737 AC XY: 1AN XY: 135658
GnomAD4 exome AF: 0.00000205 AC: 3AN: 1459914Hom.: 0 Cov.: 29 AF XY: 0.00000275 AC XY: 2AN XY: 726480
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152140Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2AN XY: 74314
ClinVar
Submissions by phenotype
Cystic fibrosis Pathogenic:7
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Variant summary: CFTR c.233dupT (p.Trp79LeufsX32) 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. The variant allele was found at a frequency of 8e-06 in 250970 control chromosomes. c.233dupT has been reported in the literature in individuals affected with Cystic Fibrosis or CBAVD. These data indicate that the variant may be associated with disease. Seven clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
The CFTR c.233dup; p.Trp79LeufsTer32 variant (rs397508360), also known as 360-365insT, is reported in individuals with cystic fibrosis (see CFTR2 database, Soe 2017), and is reported in ClinVar (Variation ID: 53475). This variant is only found on two alleles in the Genome Aggregation Database, indicating it is not a common polymorphism. This variant causes a frameshift by inserting a single nucleotide, so it is predicted to result in a truncated protein or mRNA subject to nonsense-mediated decay. Based on available information, this variant is considered to be pathogenic. References: Link to CFTR2 database: https://cftr2.org/ Soe K et al. A rare CFTR mutation associated with severe disease progression in a 10-year-old Hispanic patient. Clin Case Rep. 2017 Jan 19;5(2):139-144. PMID: 28174639. -
The c.233dupT pathogenic mutation (also known as 365_366insT), located in coding exon 3 of the CFTR gene, results from a duplication of T at nucleotide position 233, causing a translational frameshift with a predicted alternate stop codon (p.W79Lfs*32). This mutation was reported in a individual with cystic fibrosis (CF) and a pathogenic CFTR alteration, as well as in an individual with congenital bilateral absence of the vas deferens (CBAVD) with the 5T variant; however, the phase (whether in cis or trans) is not known for either individual (Alper OM et al. Hum. Mutat., 2004 Oct;24:353; Steiner B et al. Hum. Mutat., 2011 Aug;32:912-20). This mutation was also identified in a homozygous individual with pancreatic insufficient CF (Soe K et al. Clin Case Rep, 2017 Feb;5:139-144). 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. -
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This sequence change creates a premature translational stop signal (p.Trp79Leufs*32) 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). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This premature translational stop signal has been observed in individual(s) with cystic fibrosis and chronic pancreatitis (PMID: 15300780, 21520337, 28174639). ClinVar contains an entry for this variant (Variation ID: 53475). For these reasons, this variant has been classified as Pathogenic. -
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not provided Pathogenic:2
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CFTR-related disorder 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