9-95172148-C-T

Position:

• chr9-95172148-C-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000136.3(FANCC):​c.346-1G>A variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.00000209 in 1,435,250 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: FANCC NM_000136.3 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:9
• Conservation: PhyloP100: 4.55

Genes affected

FANCC (HGNC:3584): (FA complementation group C) The Fanconi anemia complementation group (FANC) currently includes FANCA, FANCB, FANCC, FANCD1 (also called BRCA2), FANCD2, FANCE, FANCF, FANCG, FANCI, FANCJ (also called BRIP1), FANCL, FANCM and FANCN (also called PALB2). The previously defined group FANCH is the same as FANCA. Fanconi anemia is a genetically heterogeneous recessive disorder characterized by cytogenetic instability, hypersensitivity to DNA crosslinking agents, increased chromosomal breakage, and defective DNA repair. The members of the Fanconi anemia complementation group do not share sequence similarity; they are related by their assembly into a common nuclear protein complex. This gene encodes the protein for complementation group C. [provided by RefSeq, Jul 2008]

FANCC (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.065593325 fraction of the gene. Cryptic splice site detected, with MaxEntScore 9.5, offset of 1, new splice context is: ttctgtttatgttttttaAGgtg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 9-95172148-C-T is Pathogenic according to our data. Variant chr9-95172148-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 522633.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-95172148-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FANCC	NM_000136.3	c.346-1G>A		splice_acceptor_variant, intron_variant		ENST00000289081.8	NP_000127.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FANCC	ENST00000289081.8	c.346-1G>A		splice_acceptor_variant, intron_variant		1	NM_000136.3	ENSP00000289081.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000209 AC: 3 AN: 1435250 Hom.: 0 Cov.: 25 AF XY: 0.00000280 AC XY: 2 AN XY: 715520

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000275

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:9

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Fanconi anemia complementation group C Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Dec 30, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genomic Research Center, Shahid Beheshti University of Medical Sciences	May 03, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Apr 24, 2024	- -

Fanconi anemia Pathogenic:2

Likely pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Nov 09, 2017	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 14, 2023	This sequence change affects an acceptor splice site in intron 4 of the FANCC gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in FANCC are known to be pathogenic (PMID: 17924555). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with breast cancer (PMID: 31300551). ClinVar contains an entry for this variant (Variation ID: 522633). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

not provided Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Sep 23, 2020	Canonical splice site variant predicted to result in an in-frame deletion of exon 5, which would disrupt the GRP94, FAZF, Hsp70 and RED binding sites (Gordon 2000); Not observed in large population cohorts (Lek 2016); Observed in individuals with advanced cancer (Schrader 2016); This variant is associated with the following publications: (PMID: 31300551, 27533158, 26556299) -
Pathogenic, no assertion criteria provided	curation	Leiden Open Variation Database	Feb 28, 2020	Curator: Arleen D. Auerbach. Submitter to LOVD: Florentia Fostira. -

FANCC-related disorder Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Apr 28, 2023

The FANCC c.346-1G>A variant is predicted to disrupt the AG splice acceptor site and interfere with normal splicing. This variant was reported in an individual with triple-negative breast cancer (Patient F2516 in Supplementary Table 3, Fostira et al. 2020. PubMed ID: 31300551) and in a patient with salivary carcinoma (Patient ID: EO4X in Supplemental Table 7, Schrader et al 2016. PubMed ID: 26556299). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Variants that disrupt the consensus splice acceptor site in FANCC are expected to be pathogenic. This variant is interpreted as likely pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 18, 2024

The c.346-1G>A intronic variant results from a G to A substitution one nucleotide before coding exon 4 of the FANCC gene. This alteration has been reported in the germline of an individual with salivary carcinoma from a cohort of patients with advanced cancer diagnoses who underwent tumor-normal sequencing (Schrader KA et al. JAMA Oncol, 2016 Jan;2:104-11). This alteration has also been reported in an individual diagnosed with early-onset breast cancer (Fostira F et al. J. Med. Genet., 2020 01;57:53-61). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that the strength of the native acceptor splice site is maintained, but shifted upstream one nucleotide resulting in a translational frameshift with a predicted alternate stop codon; however, direct evidence is unavailable. In addition to the clinical data presented in the literature, alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	35
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Uncertain	0.96	D
GERP RS		5.3

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.96		Position offset: -2
DS_AL_spliceai		0.99		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1484503633; hg19: chr9-97934430;