rs762962010

chr22-23803401-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 1P and 1B. PP2 BP4

The NM_003073.5(SMARCB1):c.607G>A(p.Ala203Thr) variant causes a missense change. The variant allele was found at a frequency of 0.0000171 in 1,461,808 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. A203A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.000017 (1 hom.)
• Consequence: SMARCB1 NM_003073.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5 B:1
• Conservation: PhyloP100: 6.86

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PP2: Missense variant where missense usually causes diseases, SMARCB1
• BP4: Computational evidence support a benign effect (MetaRNN=0.3064434).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMARCB1	NM_003073.5	c.607G>A	p.Ala203Thr	missense_variant	5/9	ENST00000644036.2
SMARCB1	NM_001362877.2	c.661G>A	p.Ala221Thr	missense_variant	5/9
SMARCB1	NM_001317946.2	c.634G>A	p.Ala212Thr	missense_variant	5/9
SMARCB1	NM_001007468.3	c.580G>A	p.Ala194Thr	missense_variant	5/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMARCB1	ENST00000644036.2	c.607G>A	p.Ala203Thr	missense_variant	5/9		NM_003073.5	A1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD3 exomes AF: 0.0000159 AC: 4 AN: 251280 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135828

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000352

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000171 AC: 25 AN: 1461808 Hom.: 1 Cov.: 34 AF XY: 0.0000179 AC XY: 13 AN XY: 727202

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000504

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000198

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

Alfa AF: 0.0000988 Hom.: 0

Bravo AF: 0.00000756

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Rhabdoid tumor predisposition syndrome 1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	Oct 24, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Schwannomatosis 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Rhabdoid tumor predisposition syndrome 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

St. Jude Molecular Pathology, St. Jude Children's Research Hospital

Dec 08, 2021

The SMARCB1 c.607G>A (p.Ala203Thr) missense change has a maximum subpopulation frequency of 0.0035% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/variant/22-24145588-G-A?dataset=gnomad_r2_1). Four of six in silico tools predict a benign effect of this variant on protein function (BP4), but to our knowledge these predictions have not been confirmed by functional assays. This variant occurs in a gene where missense variants are more likely to be damaging based on methods described by Lek et al. (PP2; PMID: 27535533). To our knowledge, this variant has not been reported in individuals with rhabdoid tumor predisposition syndrome. In summary, this variant meets criteria to be classified as of uncertain significance based on the ACMG/AMP criteria: BP4, PP2. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 30, 2023

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 203 of the SMARCB1 protein (p.Ala203Thr). This variant is present in population databases (rs762962010, gnomAD 0.004%). 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: 340912). 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 not expected to disrupt SMARCB1 protein function with a negative 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. -

Hereditary cancer-predisposing syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 06, 2021

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.087	T
BayesDel_noAF	Benign	-0.26
Cadd	Benign	23
Dann	Benign	0.94
Eigen	Benign	-0.42
Eigen_PC	Benign	-0.11
FATHMM_MKL	Uncertain	0.87	D
M_CAP	Benign	0.025	T
MetaRNN	Benign	0.31	T;T;T;T;T
MetaSVM	Benign	-0.85	T
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Benign	1.9	N;.;N;.;N
REVEL	Benign	0.28
Sift	Benign	1.0	T;.;T;.;T
Sift4G	Benign	1.0	T;.;T;.;T
Polyphen		0.0	.;B;B;.;.
Vest4		0.58
MVP		0.24
MPC		1.3
ClinPred		0.24	T
GERP RS		4.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.39
gMVP		0.72

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: rs762962010; hg19: chr22-24145588; COSMIC: COSV54098356; COSMIC: COSV54098356;