Genetic Variant SF3B1:p.Arg702Trp (chr2-197402104-G-A) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_012433.4(SF3B1):c.2104C>T(p.Arg702Trp) variant causes a missense change. The variant allele was found at a frequency of 0.000000688 in 1,453,804 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. R702R) has been classified as Benign.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

SF3B1
NM_012433.4 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.13

Publications

8 publications found

Variant links:

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]

SF3B1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.95

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SF3B1	NM_012433.4 link	c.2104C>T	p.Arg702Trp	missense_variant	Exon 15 of 25	ENST00000335508.11	NP_036565.2	O75533-1B4DGZ4
SF3B1	XM_047443838.1 link	c.1666C>T	p.Arg556Trp	missense_variant	Exon 12 of 22		XP_047299794.1
SF3B1	XM_047443839.1 link	c.1666C>T	p.Arg556Trp	missense_variant	Exon 12 of 22		XP_047299795.1
SF3B1	XM_047443840.1 link	c.2104C>T	p.Arg702Trp	missense_variant	Exon 15 of 22		XP_047299796.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SF3B1	ENST00000335508.11 link	c.2104C>T	p.Arg702Trp	missense_variant	Exon 15 of 25	1	NM_012433.4	ENSP00000335321.6		O75533-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000405

AC:

AN:

246834

AF XY:

0.00000748

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000305

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.88e-7

AC:

AN:

1453804

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

722378

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33080

American (AMR)

AF:

0.0000232

AC:

AN:

43102

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25978

East Asian (EAS)

AF:

0.00

AC:

AN:

39536

South Asian (SAS)

AF:

0.00

AC:

AN:

85568

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53342

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5748

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1107408

Other (OTH)

AF:

0.00

AC:

AN:

60042

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.37

BayesDel_noAF

Pathogenic

0.38

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.77

Eigen

Pathogenic

0.91

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Pathogenic

1.0

M_CAP

Uncertain

0.25

MetaRNN

Pathogenic

0.95

MetaSVM

Uncertain

0.74

MutationAssessor

Pathogenic

3.7

PhyloP100

7.1

PrimateAI

Pathogenic

0.94

PROVEAN

Pathogenic

-7.3

REVEL

Pathogenic

0.87

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.94

MutPred

0.80

Loss of disorder (P = 0.0329);

MVP

0.88

MPC

2.9

ClinPred

0.99

GERP RS

5.1

Varity_R

0.91

gMVP

0.97

Mutation Taster

=36/64

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over