NM_000492.4:c.1043T>A
Variant summary
Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM1PP2PP3_ModerateBP6
The NM_000492.4(CFTR):c.1043T>A(p.Met348Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000123 in 1,613,968 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M348T) 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 4 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt | 
|---|---|---|---|---|---|---|---|---|
| CFTR | NM_000492.4  | c.1043T>A | p.Met348Lys | missense_variant | Exon 8 of 27 | ENST00000003084.11 | NP_000483.3 | 
Ensembl
Frequencies
GnomAD3 genomes   AF:  0.0000788  AC: 12AN: 152188Hom.:  0  Cov.: 32 show subpopulations 
GnomAD2 exomes  AF:  0.000135  AC: 34AN: 251176 AF XY:  0.000169   show subpopulations 
GnomAD4 exome  AF:  0.000128  AC: 187AN: 1461780Hom.:  0  Cov.: 31 AF XY:  0.000135  AC XY: 98AN XY: 727182 show subpopulations 
Age Distribution
GnomAD4 genome   AF:  0.0000788  AC: 12AN: 152188Hom.:  0  Cov.: 32 AF XY:  0.0000538  AC XY: 4AN XY: 74352 show subpopulations 
Age Distribution
ClinVar
Submissions by phenotype
Cystic fibrosis    Uncertain:3Benign:5 
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This submission and the accompanying classification are no longer maintained by the submitter.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. -
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This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
not provided    Uncertain:1Benign:2 
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CFTR: PM1, PP3, BP2, BS3:Supporting, BS4 -
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not specified    Benign:1 
Variant summary: CFTR c.1043T>A (p.Met348Lys) results in a non-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. The variant allele was found at a frequency of 0.00014 in 251178 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in CFTR causing Cystic Fibrosis (0.00014 vs 0.013), allowing no conclusion about variant significance. c.1043T>A has been reported in the literature in individuals affected with Cystic Fibrosis (CF) (example: DApice_2004, Liechti-Gallati_1999). However, it has also been found in a healthy homozygous individual (Molinario_2013) and in a patient who presented with respiratory distress, necrotizing enterocolitis and hyperbilirubinemia but a negative sweat test (Hentschel_2012), indicating the variant was not causative for CF. In another family the variant was shown not to co-segregate with the disease (D'Apice_2004). Additionally, the variant has also been found in cis with another pathogenic variant in a CBAVD (Congenital Bilateral Absence of Vas Deferens) and a CF patient with pancreatic insufficiency (Lucarelli_2015). Electrophysiological assessment of CFTR in native rectal epithelium of the patient homozygous for this variant demonstrated normal Cl- secretion (Hentschel_2012) and Gt channel conductance was 61% of normal relative to wildtype (Bihler_2024). The following publications have been ascertained in the context of this evaluation (PMID: 38388235, 32357917, 15084222, 15614862, 22274833, 16128988, 10439967, 25910067, 23951356, 25922769, 28801929, 30134826, 25087612, 26436105). ClinVar contains an entry for this variant (Variation ID: 53173). Based on the evidence outlined above, the variant was classified as likely benign. -
CFTR-related disorder    Benign:1 
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
Computational scores
Source: 
Splicing
 Find out detailed SpliceAI scores and Pangolin per-transcript scores at