22-23816814-G-T

Position:

• chr22-23816814-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Strong

The NM_003073.5(SMARCB1):​c.673G>T​(p.Asp225Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,704 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SMARCB1 NM_003073.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 9.94

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 Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SMARCB1. . Gene score misZ 3.6016 (greater than the threshold 3.09). Trascript score misZ 4.8554 (greater than threshold 3.09). GenCC has associacion of gene with schwannomatosis 1, familial multiple meningioma, rhabdoid tumor predisposition syndrome 1, complex neurodevelopmental disorder, intellectual disability, autosomal dominant 15, familial rhabdoid tumor, schwannomatosis, Coffin-Siris syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SMARCB1	NM_003073.5	c.673G>T	p.Asp225Tyr	missense_variant	6/9	ENST00000644036.2	NP_003064.2
SMARCB1	NM_001362877.2	c.727G>T	p.Asp243Tyr	missense_variant	6/9		NP_001349806.1
SMARCB1	NM_001317946.2	c.700G>T	p.Asp234Tyr	missense_variant	6/9		NP_001304875.1
SMARCB1	NM_001007468.3	c.646G>T	p.Asp216Tyr	missense_variant	6/9		NP_001007469.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SMARCB1	ENST00000644036.2	c.673G>T	p.Asp225Tyr	missense_variant	6/9		NM_003073.5	ENSP00000494049	A1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461704 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727176

Gnomad4 AFR exome AF: 0.0000299

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.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Rhabdoid tumor predisposition syndrome 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Nov 02, 2023

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 09, 2023

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. 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. ClinVar contains an entry for this variant (Variation ID: 581167). This variant has not been reported in the literature in individuals affected with SMARCB1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces aspartic acid, which is acidic and polar, with tyrosine, which is neutral and polar, at codon 225 of the SMARCB1 protein (p.Asp225Tyr). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 21, 2022

The p.D225Y variant (also known as c.673G>T), located in coding exon 6 of the SMARCB1 gene, results from a G to T substitution at nucleotide position 673. The aspartic acid at codon 225 is replaced by tyrosine, an amino acid with highly dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Missense and in-frame variants in SMARCB1 are known to cause neurodevelopmental disorders; however, such associations with rhabdoid tumor predisposition syndrome are exceedingly rare (Kosho T et al. Am J Med Genet C Semin Med Genet. 2014 Sep;166C(3):262-75; Eaton KW et al. Pediatr Blood Cancer. 2011 Jan;56(1):7-15). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	33
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.93	.;D;D;.;.
Eigen	Pathogenic	0.79
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	.;.;.;.;D
M_CAP	Pathogenic	0.36	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Pathogenic	3.9	.;H;.;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-7.8	D;.;D;.;.
REVEL	Pathogenic	0.92
Sift	Pathogenic	0.0	D;.;D;.;.
Sift4G	Pathogenic	0.0010	D;.;D;.;.
Polyphen		0.53, 0.97	.;P;D;.;.
Vest4		0.97
MutPred		0.92		.;.;Loss of catalytic residue at D234 (P = 0.2261);.;.;
MVP		0.99
MPC		2.8
ClinPred		1.0	D
GERP RS		5.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.99
gMVP		0.97

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: rs768379745; hg19: chr22-24159001;