chr15-89268467-T-C
Variant summary
Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong
The NM_001113378.2(FANCI):āc.824T>Cā(p.Ile275Thr) variant causes a missense change. The variant allele was found at a frequency of 0.000649 in 1,614,172 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign 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. I275V) has been classified as Uncertain significance.
Frequency
Consequence
NM_001113378.2 missense
Scores
Clinical Significance
Conservation
Publications
- Fanconi anemia complementation group IInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P
- Fanconi anemiaInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Likely_benign. The variant received -4 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000677 AC: 103AN: 152186Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.000553 AC: 139AN: 251470 AF XY: 0.000596 show subpopulations
GnomAD4 exome AF: 0.000646 AC: 945AN: 1461868Hom.: 0 Cov.: 32 AF XY: 0.000672 AC XY: 489AN XY: 727230 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000676 AC: 103AN: 152304Hom.: 0 Cov.: 32 AF XY: 0.000631 AC XY: 47AN XY: 74466 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:3
Reported in two unrelated individuals with head and neck squamous cell carcinoma, each of whom also harbored variants in other genes associated with this diagnosis (PMID: 28678401); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 30303537, 34861889, 28678401, 32546565, 36461907) -
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Fanconi anemia complementation group I Uncertain:3
This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
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Fanconi anemia Uncertain:2
This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 275 of the FANCI protein (p.Ile275Thr). This variant is present in population databases (rs142906652, gnomAD 0.1%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with head and neck squamous cell carcinoma, breast cancer and/or suspected Lynch syndrome (PMID: 28678401, 30303537, 36356413). ClinVar contains an entry for this variant (Variation ID: 449021). 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 not expected to disrupt FANCI protein function with a negative predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
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not specified Uncertain:1Benign:1
DNA sequence analysis of the FANCI gene demonstrated a sequence change, c.824T>C, in exon 10 that results in an amino acid change, p.Ile275Thr. This sequence change has been described in the gnomAD database with a frequency of 0.11% in the European sub-population (dbSNP rs142906652). The p.Ile275Thr change has been described in one individual with head and neck squamous cell carcinoma (PMID: 28678401). The p.Ile275Thr change affects a highly conserved amino acid residue located in a domain of the FANCI protein that is not known to be functional. In-silico predictions pathogenicity prediction tools (SIFT, PoluPhen2, Align GVGD, REVEL) provide contradictory results for the p.Ile275Thr substitution. Due to these contrasting evidences and the lack of functional studies, the clinical significance of the p.Ile275Thr change remains unknown at this time. -
Variant summary: FANCI c.824T>C (p.Ile275Thr) results in a non-conservative amino acid change located in the FANCI solenoid 1 domain of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00055 in 251470 control chromosomes. The observed variant frequency is approximately 1.98 fold of the estimated maximal expected allele frequency for a pathogenic variant in FANCI causing Fanconi Anemia phenotype (0.00028), strongly suggesting that the variant is benign. c.824T>C has been reported in the literature in individuals affected with various cancer phenotypes including colorectal, head and neck and breast cancer (Poliani_2022, Chandrasekharappa_2018, Girard_2019). These reports do not provide unequivocal conclusions about association of the variant with Fanconi Anemia. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 28678401, 30303537, 36356413). Eight submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as likely benign. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at