chr7-117535269-G-A
Variant summary
Our verdict is Uncertain significance. The variant received 1 ACMG points: 3P and 2B. PM1PP2BP4_Moderate
The NM_000492.4(CFTR):c.601G>A(p.Val201Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000169 in 1,614,044 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★★). Synonymous variant affecting the same amino acid position (i.e. V201V) has been classified as Likely benign.
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 1 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| CFTR | NM_000492.4 | c.601G>A | p.Val201Met | missense_variant | Exon 6 of 27 | ENST00000003084.11 | NP_000483.3 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| CFTR | ENST00000003084.11 | c.601G>A | p.Val201Met | missense_variant | Exon 6 of 27 | 1 | NM_000492.4 | ENSP00000003084.6 |
Frequencies
GnomAD3 genomes AF: 0.000467 AC: 71AN: 152068Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.000231 AC: 58AN: 251432 AF XY: 0.000243 show subpopulations
GnomAD4 exome AF: 0.000137 AC: 201AN: 1461858Hom.: 1 Cov.: 32 AF XY: 0.000138 AC XY: 100AN XY: 727228 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000467 AC: 71AN: 152186Hom.: 0 Cov.: 32 AF XY: 0.000497 AC XY: 37AN XY: 74408 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Cystic fibrosis Pathogenic:3Uncertain:7
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This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 201 of the CFTR protein (p.Val201Met). This variant is present in population databases (rs138338446, gnomAD 0.07%), including at least one homozygous and/or hemizygous individual. This missense change has been observed in individual(s) with cystic fibrosis or congenital bilateral absence of the vas deferens (PMID: 15287992, 16963320, 19897426, 21520337, 21658649, 25910067, 27738188, 30232781; internal data). 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: 54022). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) 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: 21708286, 27738188). For these reasons, this variant has been classified as Pathogenic. -
CFTR variant of uncertain clinical significance. See www.CFTR2.org for phenotype information. -
Variant NM_000492.4(CFTR):c.601G>A (p.Val201Met) has GnomAD 4.1 frequency of 0.0001685 with 1 homozygote. Reported as likely pathogenic in PMID 29805046 -
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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Variant summary: CFTR c.601G>A (p.Val201Met) results in a conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change. The variant allele was found at a frequency of 0.00023 in 251432 control chromosomes in the gnomAD database, including 1 homozygote. This frequency is not significantly higher than estimated for a pathogenic variant in CFTR causing Non-Classic Cystic Fibrosis (0.00023 vs 0.013), allowing no conclusion about variant significance. c.601G>A has been observed in the presumed or confirmed compound heterozygous state as an isolated variant allele (i.e. not on a haplotype) in multiple individuals affected with primarily Non-Classic Cystic Fibrosis (CBAVD, Cystic Fibrosis Screening Positive Inconclusive Diagnosis [CFSPID], sweat test-positive newborn screening with presumptive diagnosis of CF, CF-related conditions) (example, Boudaya_2012, Steiner_2011, Mota_2018, Girardet_2015, Thimmesch_2024, Castaldo_2020, Hu_2024, CFTR-France Database, internal data). These data indicate that the variant in isolation is very likely to be associated with primarily mild-spectrum CFTR-related disease. Further, the V201M component of the common pathogenic haplotype p.[R74W;V201M;D1270N] is considered by our laboratory to be the primary variation responsible for clinical presentation, as the other 2 variants R74W and D1270N are likely to be in cis and approach or exceed (0.01253-0.01388 with 3-10 homozygotes across gnomAD v2/v4) the maximum expected pathogenic allele frequency for CFTR-related conditions (0.013), yet lack robust clinical data when alone (ClinVar). In at least 1 study, p.[R74W;D1270N] in the absence of V201M was observed in trans with a well-established pathogenic variant in an unaffected female individual with multiple negative sweat test results (Claustres_2004), suggesting p.[R74W;D1270N] is unlikely to cause severe non-CBAVD CFTR-related disease in the absence of V201M. At least one publication reports experimental evidence evaluating an impact on protein function for isolated V201M in vitro. The most pronounced isolated variant effect resulted in approximately 23.43% of normal chloride channel conductance relative to wild type, as compared to R74W (37.4%) or D1270N (50.95%) in isolation or 5.97% for the p.[R74W;V201M;D1270N] haplotype (e.g., Bihler_2024). The following publications have been ascertained in the context of this evaluation (PMID: 10794365, 22148899, 36796836, 32357917, 14998948, 20021716, 38695616, 36832409, 29805046, 37431359, 30232781, 36409994, 21520337, 27738188, 20217271, 15905293, 36834620, 38388235, 39570414, 38388235, 32784480, 39402445, 24762087, 15287992). ClinVar contains an entry for this variant (Variation ID: 54022). Based on the evidence outlined above, the variant was classified as pathogenic, whether on the haplotype or in isolation. -
The p.V201M variant (also known as c.601G>A), located in coding exon 6 of the CFTR gene, results from a G to A substitution at nucleotide position 601. The valine at codon 201 is replaced by methionine, an amino acid with highly similar properties. This variant was identified in isolation in a child with mild pulmonary disease, pancreatic sufficiency, and elevated sweat chloride; however, a second alteration was not identified (Bernardino AL et al. Genet Test, 2000;4:69-74). In addition, this variant has been detected in conjunction with a pathogenic CFTR variant in a child with elevated sweat chloride levels and a man with congenital absence of the vas deferens (CBAVD) (Mota LR et al. Mol Biol Rep, 2018 Dec;45:2045-2051; Steiner B et al. Hum Mutat, 2011 Aug;32:912-20). This variant often occurs as part of a complex allele, p.[R74W;R1070W;D1270N]. The complex allele has been identified in the homozygous state and in trans with a pathogenic CFTR mutation in multiple individuals with cystic fibrosis and CFTR-related disorders (Claustres M et al. BMC Med Genet, 2004 Aug;5:19; Steiner B et al. Hum Mutat, 2011 Aug;32:912-20; Lucarelli M et al. Mol Med, 2015 Apr;21:257-75; Terlizzi V et al. J Med Genet, 2017 Apr;54:224-235). In one report, two young boys carried the complex allele in trans with p.F508del and were asymptomatic; however, CBAVD was not ruled out (Brugnon F et al. Fertil. Steril., 2008 Nov;90:2004.e23-6). Functional studies demonstrated that this variant on its own reduces CFTR activity, but the presence of the other variants (p.R74W and p.D1270N) in cis results in further reduction (Raraigh KS et al. Am J Hum Genet, 2018 Jun;102:1062-1077; Bihler H et al. J Cyst Fibros, 2024 Jul;23:664-675). This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -
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not provided Uncertain:6
The CFTR c.601G>A; p.Val201Met variant (rs138338446) has been identified without an additional pathogenic variant in an individual with a clinical diagnosis of cystic fibrosis (CF), individuals with congenital bilateral absence of the vas deferens (CBAVD) (Bernardino 2000, Gallati 2009, Luo 2021, Steiner 2011, Wu 2005), and in one individual with CBAVD who also carried a severe pathogenic variant (Steiner 2011). However, this variant is most often identified in individuals with atypical CF as part of a complex variant on the same allele as other variants (Behar 2017, Brugnon 2008, Claustres 2004, Masson 2013, Steiner 2011, Terlizzi 2017). This variant is reported as an uncertain variant in ClinVar (Variation ID: 54022), and is found in the general population with an overall allele frequency of 0.02% (61/282812 alleles, including a single homozygote) in the Genome Aggregation Database (v2.1.1). Computational analyses are uncertain whether this variant is neutral or deleterious (REVEL: 0.676). Considering available information, the clinical significance of this variant cannot be determined with certainty. References: Behar DM et al. Nationwide genetic analysis for molecularly unresolved cystic fibrosis patients in a multiethnic society: implications for preconception carrier screening. Mol Genet Genomic Med. 2017 Feb 19;5(3):223-236. PMID: 28546993. Bernardino AL et al. Molecular analysis in Brazilian cystic fibrosis patients reveals five novel mutations. Genet Test. 2000;4(1):69-74. PMID: 10794365. Brugnon F et al. Outcome of intracytoplasmic sperm injection for a couple in which the man is carrier of CFTR p.[R74W;V201M;D1270N] and p.P841R mutations and his spouse a heterozygous carrier of p.F508del mutation of the cystic fibrosis transmembrane conductance regulator gene. Fertil Steril. 2008 Nov;90(5):2004.e23-6. PMID: 18703181. Claustres M et al. Are p.I148T, p.R74W and p.D1270N cystic fibrosis causing mutations? BMC Med Genet. 2004 Aug 2;5:19. PMID: 15287992. Gallati S et al. Cystic fibrosis transmembrane conductance regulator mutations in azoospermic and oligospermic men and their partners. Reprod Biomed Online. 2009 Nov;19(5):685-94. PMID: 20021716. Luo S et al. Mutation analysis of the cystic fibrosis transmembrane conductance regulator gene in Chinese congenital absence of vas deferens patients. Gene. 2021 Jan 10;765:145045. PMID: 32777524. Masson E et al. A conservative assessment of the major genetic causes of idiopathic chronic pancreatitis: data from a comprehensive analysis of PRSS1, SPINK1, CTRC and CFTR genes in 253 young French patients. PLoS One. 2013 Aug 8;8(8):e73522. PMID: 23951356. Steiner B et al. Common CFTR haplotypes and susceptibility to chronic pancreatitis and congenital bilateral absence of the vas deferens. Hum Mutat. 2011 Aug;32(8):912-20. PMID: 21520337. Terlizzi V et al. Genotype-phenotype correlation and functional studies in patients with cystic fibrosis bearing CFTR complex alleles. J Med Genet. 2017 Apr;54(4):224-235. PMID: 27738188. Wu CC et al. Mutation spectrum of the CFTR gene in Taiwanese patients with congenital bilateral absence of the vas deferens. Hum Reprod. 2005 Sep;20(9):2470-5. PMID: 15905293. -
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The V201M variant in the CFTR gene has been reported previously as heterozygous in one child diagnosed with CF; no other variants in the CFTR gene were identified (Bernardino et al., 2000). The V201M variant was not observed with any significant frequency in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The V201M variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. This substitution occurs at a position where amino acids with similar properties to Valine are tolerated across species. In silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. Pathogenic missense variants in nearby residues (H199Y, P205S) have been reported in the Human Gene Mutation Database in association with CF (Stenson et al., 2014), supporting the functional importance of this region of the protein. We interpret V201M as a variant of uncertain significance. -
The CFTR c.601G>A (p.Val201Met) variant (also known as V201M) has been reported in the published literature in individuals affected with CF (PMID: 32819855 (2020)), congenital bilateral absence of the vas deferens (CBAVD) (PMID: 15905293 (2005), 22148899 (2012), 32777524 (2021)), in a child with a diagnosis of CF without a second mutation (PMID: 10794365 (2000)), and in a newborn carrying a pathogenic variant with normal sweat chloride but an elevated immunoreactive trypsin (IRT) (PMID: 30232781 (2018)). It was also identified in a cohort of infertile individuals (PMID: 32357917 (2020)). In addition, an experimental study indicated the variant has reduced CFTR activity, however with an inconclusive effect (PMID: 29805046 (2018)). The frequency of this variant in the general population, 0.0006208 (22/35436 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded conflicting predictions that this variant is benign or damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -
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CFTR-related disorder Uncertain:2
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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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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at