22-23816931-A-T

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM2PP3_Moderate

The NM_003073.5(SMARCB1):c.790A>T(p.Ile264Phe) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,472 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I264V) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

SMARCB1
NM_003073.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 7.48

Publications

1 publications found

Variant links:

Genes affected

SMARCB1 (HGNC:11103): (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily b, member 1) The protein encoded by this gene is part of a complex that relieves repressive chromatin structures, allowing the transcriptional machinery to access its targets more effectively. The encoded nuclear protein may also bind to and enhance the DNA joining activity of HIV-1 integrase. This gene has been found to be a tumor suppressor, and mutations in it have been associated with malignant rhabdoid tumors. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Dec 2015]

SMARCB1 Gene-Disease associations (from GenCC):

Coffin-Siris syndrome
Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
intellectual disability, autosomal dominant 15
Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
rhabdoid tumor predisposition syndrome 1
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen
SMARCB1-related schwannomatosis
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Ambry Genetics
familial multiple meningioma
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
familial rhabdoid tumor
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
schwannomatosis
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
complex neurodevelopmental disorder
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

SMARCB1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 15 uncertain in NM_003073.5

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.862

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMARCB1	NM_003073.5 link	c.790A>T	p.Ile264Phe	missense_variant	Exon 6 of 9	ENST00000644036.2	NP_003064.2	Q12824-1
SMARCB1	NM_001362877.2 link	c.844A>T	p.Ile282Phe	missense_variant	Exon 6 of 9		NP_001349806.1
SMARCB1	NM_001317946.2 link	c.817A>T	p.Ile273Phe	missense_variant	Exon 6 of 9		NP_001304875.1	G5E975Q9H836
SMARCB1	NM_001007468.3 link	c.763A>T	p.Ile255Phe	missense_variant	Exon 6 of 9		NP_001007469.1	Q12824-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMARCB1	ENST00000644036.2 link	c.790A>T	p.Ile264Phe	missense_variant	Exon 6 of 9		NM_003073.5	ENSP00000494049.2		Q12824-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461472

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727090

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:

33476

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53170

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111858

Other (OTH)

AF:

0.00

AC:

AN:

60386

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.275

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Jul 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 264 of the SMARCB1 protein (p.Ile264Phe). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SMARCB1-related conditions. ClinVar contains an entry for this variant (Variation ID: 1021461). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SMARCB1 protein function with a positive predictive value of 80%. 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

AlphaMissense

Pathogenic

0.95

BayesDel_addAF

Pathogenic

0.43

BayesDel_noAF

Pathogenic

0.39

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.88

.;D;T;.

Eigen

Uncertain

0.43

Eigen_PC

Uncertain

0.46

FATHMM_MKL

Pathogenic

0.98

M_CAP

Uncertain

0.22

MetaRNN

Pathogenic

0.86

D;D;D;D

MetaSVM

Uncertain

0.52

MutationAssessor

Pathogenic

3.4

.;M;.;.

PhyloP100

7.5

PrimateAI

Pathogenic

0.88

PROVEAN

Uncertain

-3.1

D;.;D;.

REVEL

Pathogenic

0.88

Sift

Uncertain

0.0030

D;.;D;.

Sift4G

Uncertain

0.0090

D;.;D;.

Polyphen

0.60, 0.12

.;P;B;.

Vest4

0.92

MutPred

0.62

.;.;Gain of methylation at K274 (P = 0.0395);.;

MVP

0.99

MPC

3.0

ClinPred

0.95

GERP RS

5.1

Varity_R

0.80

gMVP

0.97

Mutation Taster

=16/84

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over