rs137942040

chr22-23833572-C-Achr22-23833572-C-Gchr22-23833572-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_003073.5(SMARCB1):c.987C>A(p.Ser329Arg) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 3/3 splice prediction tools predict no significant impact on normal splicing. 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. S329G) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: SMARCB1 NM_003073.5 missense, splice_region
• Scores: Splicing: ADA: 0.00005679
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.205

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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, SMARCB1

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMARCB1	NM_003073.5	c.987C>A	p.Ser329Arg	missense_variant, splice_region_variant	8/9	ENST00000644036.2
SMARCB1	NM_001362877.2	c.1041C>A	p.Ser347Arg	missense_variant, splice_region_variant	8/9
SMARCB1	NM_001317946.2	c.1014C>A	p.Ser338Arg	missense_variant, splice_region_variant	8/9
SMARCB1	NM_001007468.3	c.960C>A	p.Ser320Arg	missense_variant, splice_region_variant	8/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMARCB1	ENST00000644036.2	c.987C>A	p.Ser329Arg	missense_variant, splice_region_variant	8/9		NM_003073.5	A1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 12, 2019

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with SMARCB1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces serine with arginine at codon 329 of the SMARCB1 protein (p.Ser329Arg). The serine residue is highly conserved and there is a moderate physicochemical difference between serine and arginine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.17
Cadd	Benign	18
Dann	Benign	0.97
Eigen	Benign	-0.56
Eigen_PC	Benign	-0.51
FATHMM_MKL	Benign	0.70	D
M_CAP	Uncertain	0.24	D
MetaRNN	Uncertain	0.51	D;D;D;D
MetaSVM	Benign	-0.71	T
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.91	D
PROVEAN	Uncertain	-3.2	D;.;D;.
REVEL	Uncertain	0.50
Sift	Benign	0.063	T;.;D;.
Sift4G	Benign	0.090	T;.;T;.
Polyphen		0.062, 0.029	.;B;B;.
Vest4		0.81
MutPred		0.48		.;.;Loss of ubiquitination at K333 (P = 0.0332);.;
MVP		0.97
MPC		1.5
ClinPred		0.73	D
GERP RS		1.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.63
gMVP		0.99

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000057
dbscSNV1_RF	Benign	0.0020
SpliceAI score (max)		0.040		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: rs137942040; hg19: chr22-24175759;