rs765277254

Positions:

• chr16-89814614-C-A
• chr16-89814614-C-G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000135.4(FANCA):​c.190-1G>T variant causes a splice acceptor, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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)
• Consequence: FANCA NM_000135.4 splice_acceptor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 3.23

Genes affected

FANCA (HGNC:3582): (FA complementation group A) 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 A. Alternative splicing results in multiple transcript variants encoding different isoforms. Mutations in this gene are the most common cause of Fanconi anemia. [provided by RefSeq, Jul 2008]

FANCA (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 5.5, offset of 4, new splice context is: gtgttttggattctatgtAGaag. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-89814614-C-A is Pathogenic according to our data. Variant chr16-89814614-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 550259.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr16-89814614-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FANCA	NM_000135.4	c.190-1G>T		splice_acceptor_variant, intron_variant		ENST00000389301.8	NP_000126.2
FANCA	NM_001286167.3	c.190-1G>T		splice_acceptor_variant, intron_variant			NP_001273096.1
FANCA	NM_001018112.3	c.190-1G>T		splice_acceptor_variant, intron_variant			NP_001018122.1
FANCA	NM_001351830.2	c.190-1G>T		splice_acceptor_variant, intron_variant			NP_001338759.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FANCA	ENST00000389301.8	c.190-1G>T		splice_acceptor_variant, intron_variant		1	NM_000135.4	ENSP00000373952.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Fanconi anemia complementation group A Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Dec 27, 2016	- -
Pathogenic, no assertion criteria provided	curation	Leiden Open Variation Database	Feb 28, 2020	Curator: Arleen D. Auerbach. Submitter to LOVD: Arleen D. Auerbach. -

Fanconi anemia Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 27, 2020

For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has been observed in individual(s) with Fanconi anemia (PMID: 12955722). In at least one individual the data is consistent with the variant being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 550259). This variant is not present in population databases (ExAC no frequency). This sequence change affects an acceptor splice site in intron 2 of the FANCA 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 FANCA are known to be pathogenic (PMID: 19367192). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.050
CADD	Uncertain	25
DANN	Uncertain	0.99
Eigen	Pathogenic	0.86
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Uncertain	0.88	D
GERP RS		4.9

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.80
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.98		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: rs765277254; hg19: chr16-89881022;