9-95249289-C-T

Variant names:

• chr9-95249289-C-T
• rs1368374192
• NM_000136.3:c.3G>A

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The NM_000136.3(FANCC):​c.3G>A​(p.Met1?) variant causes a start lost change. The variant allele was found at a frequency of 0.000000684 in 1,461,770 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).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: FANCC NM_000136.3 start_lost
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 5.31
• Publications: 2 publications found

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 Gene-Disease associations (from GenCC):

• Fanconi anemia complementation group C

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P, Myriad Women’s Health
• Fanconi anemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• colorectal cancer

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• malignant pancreatic neoplasm

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• ovarian cancer

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• prostate cancer

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• breast cancer

  Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PVS1: Start lost variant, next in-frame start position is after 14 pathogenic variants. Next in-frame start position is after 16 codons. Genomic position: 95249246. Lost 0.027 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 9-95249289-C-T is Pathogenic according to our data. Variant chr9-95249289-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 632544.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FANCC	NM_000136.3	c.3G>A	p.Met1?	start_lost	Exon 2 of 15	ENST00000289081.8	NP_000127.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FANCC	ENST00000289081.8	c.3G>A	p.Met1?	start_lost	Exon 2 of 15	1	NM_000136.3	ENSP00000289081.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461770 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727192

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39692

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53352

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111974

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:1

Sep 07, 2021

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.M1? pathogenic mutation (also known as c.3G>A) is located in coding exon 1 of the FANCC gene and results from a G to A substitution at nucleotide position 3. This alters the methionine residue at the initiation codon (ATG). Sequence variations that modify the initiation codon are expected to result in either loss of translation initiation, N-terminal truncation, or cause a shift in the mRNA reading frame. Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation.

not specified Uncertain:1

Oct 15, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: FANCC c.3G>A (p.Met1Ile) alters the initiation codon and is predicted to result either in absence of the protein or truncation of the encoded protein due to translation initiation at a downstream codon; the next in-frame Methionine occurs at codon 16 in the native protein sequence. Three of four in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 250170 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.3G>A has been reported in the literature in at least one individual affected with Head and Neck Squamous Cell Carcinoma (Chandrasekharappa_2017). This report does not provide unequivocal conclusions about association of the variant with Fanconi Anemia Group C. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two ClinVar submitters have assessed the variant since 2014: both classified the variant as of uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance.

Fanconi anemia Uncertain:1

Aug 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects the initiator methionine of the FANCC mRNA. The next in-frame methionine is located at codon 16. This variant is not present in population databases (gnomAD no frequency). Disruption of the initiator codon has been observed in individual(s) with head and neck cancer (PMID: 28678401). ClinVar contains an entry for this variant (Variation ID: 632544). 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.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.21
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.57	D;D;T;.;T;.;.;.
Eigen	Pathogenic	0.71
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.0	.;D;D;D;D;D;D;D
M_CAP	Benign	0.052	D
MetaRNN	Pathogenic	0.83	D;D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.27	T
MutationAssessor	Benign	0.0	.;.;.;.;.;.;.;.
PhyloP100		5.3
PROVEAN	Uncertain	-2.7	D;D;.;.;D;.;.;.
REVEL	Uncertain	0.40
Sift	Pathogenic	0.0	D;D;.;.;D;.;.;.
Sift4G	Pathogenic	0.0	D;D;D;.;D;.;.;.
Vest4		0.91
ClinPred		0.99	D
GERP RS		5.1
PromoterAI		-0.096	Neutral
Varity_R		0.80
gMVP		0.38
Mutation Taster		=32/168	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.12		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs1368374192; hg19: chr9-98011571; COSMIC: COSV56668057;