7-117504278-G-T
Variant summary
Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000492.4(CFTR):c.79G>T(p.Gly27*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000206 in 1,458,524 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 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 18 ACMG points.
Variant Effect in Transcripts
ACMG analysis was done for transcript: NM_000492.4. You can select a different transcript below to see updated ACMG assignments.
RefSeq Transcripts
| Selected | Gene | Transcript | Tags | HGVSc | HGVSp | Effect | Exon Rank | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|---|
| CFTR | NM_000492.4 | MANE Select | c.79G>T | p.Gly27* | stop_gained | Exon 2 of 27 | NP_000483.3 |
Ensembl Transcripts
| Selected | Gene | Transcript | Tags | HGVSc | HGVSp | Effect | Exon Rank | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|---|
| CFTR | ENST00000003084.11 | TSL:1 MANE Select | c.79G>T | p.Gly27* | stop_gained | Exon 2 of 27 | ENSP00000003084.6 | ||
| CFTR | ENST00000546407.1 | TSL:1 | n.192G>T | non_coding_transcript_exon | Exon 3 of 3 | ||||
| CFTR | ENST00000699605.1 | c.-165G>T | 5_prime_UTR_premature_start_codon_gain | Exon 3 of 27 | ENSP00000514473.1 |
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD2 exomes AF: 0.00000399 AC: 1AN: 250926 AF XY: 0.00 show subpopulations
GnomAD4 exome AF: 0.00000206 AC: 3AN: 1458524Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0AN XY: 725830 show subpopulations ⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
Age Distribution
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Cystic fibrosis Pathogenic:6
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.
The p.G27* pathogenic mutation (also known as c.79G>T), located in coding exon 2 of the CFTR gene, results from a G to T substitution at nucleotide position 79. This changes the amino acid from a glycine to a stop codon within coding exon 2. 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.
For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in CFTR are known to be pathogenic (PMID: 1695717, 7691345, 9725922). This variant has been observed in individual(s) with cystic fibrosis (PMID: 1284531). In at least one individual the data is consistent with the variant being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 54061). This variant is present in population databases (rs397508796, ExAC 0.002%). This sequence change creates a premature translational stop signal (p.Gly27*) in the CFTR gene. It is expected to result in an absent or disrupted protein product.
Variant summary: CFTR c.79G>T (p.Gly27X) results in a premature termination codon, predicted to cause absence of the protein due to nonsense mediated decay, which is a commonly known mechanism for disease. The variant allele was found at a frequency of 4e-06 in 250926 control chromosomes (gnomAD). c.79G>T has been reported in the literature in individuals affected with Cystic Fibrosis (e.g. Raraigh_2022). The following publication has been ascertained in the context of this evaluation (PMID: 34782259). Six submitters, including an expert panel, have provided clinical-significance assessments for this variant to ClinVar after 2014, and classified it as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic.
CFTR-related disorder Pathogenic:1
Bronchiectasis with or without elevated sweat chloride 1 Pathogenic:1
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at