2-197400802-A-T

Position:

• chr2-197400802-A-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_012433.4(SF3B1):​c.2631T>A​(p.Gly877=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. G877G) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SF3B1 NM_012433.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.494

Genes affected

SF3B1 (HGNC:10768): (splicing factor 3b subunit 1) This gene encodes subunit 1 of the splicing factor 3b protein complex. Splicing factor 3b, together with splicing factor 3a and a 12S RNA unit, forms the U2 small nuclear ribonucleoproteins complex (U2 snRNP). The splicing factor 3b/3a complex binds pre-mRNA upstream of the intron's branch site in a sequence independent manner and may anchor the U2 snRNP to the pre-mRNA. Splicing factor 3b is also a component of the minor U12-type spliceosome. The carboxy-terminal two-thirds of subunit 1 have 22 non-identical, tandem HEAT repeats that form rod-like, helical structures. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.54).
• BP7: Synonymous conserved (PhyloP=0.494 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SF3B1	NM_012433.4	c.2631T>A	p.Gly877=	synonymous_variant	18/25	ENST00000335508.11
SF3B1	XM_047443838.1	c.2193T>A	p.Gly731=	synonymous_variant	15/22
SF3B1	XM_047443839.1	c.2193T>A	p.Gly731=	synonymous_variant	15/22
SF3B1	XM_047443840.1	c.2631T>A	p.Gly877=	synonymous_variant	18/22

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SF3B1	ENST00000335508.11	c.2631T>A	p.Gly877=	synonymous_variant	18/25	1	NM_012433.4	P1
SF3B1	ENST00000470268.2	n.4515T>A		non_coding_transcript_exon_variant	17/24	2
SF3B1	ENST00000652026.1	c.*3698T>A		3_prime_UTR_variant, NMD_transcript_variant	18/25
SF3B1	ENST00000652738.1	c.*2890T>A		3_prime_UTR_variant, NMD_transcript_variant	19/26

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1460668 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 726756

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.54
CADD	Benign	8.5
DANN	Benign	0.80
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs788018; hg19: chr2-198265526;