chr22-23816854-C-T

Position:

• chr22-23816854-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.713C>T​(p.Ala238Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,492 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SMARCB1 NM_003073.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.86

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 3 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SMARCB1	NM_003073.5	c.713C>T	p.Ala238Val	missense_variant	6/9	ENST00000644036.2	NP_003064.2
SMARCB1	NM_001362877.2	c.767C>T	p.Ala256Val	missense_variant	6/9		NP_001349806.1
SMARCB1	NM_001317946.2	c.740C>T	p.Ala247Val	missense_variant	6/9		NP_001304875.1
SMARCB1	NM_001007468.3	c.686C>T	p.Ala229Val	missense_variant	6/9		NP_001007469.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SMARCB1	ENST00000644036.2	c.713C>T	p.Ala238Val	missense_variant	6/9		NM_003073.5	ENSP00000494049	A1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251420 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135896

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461492 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727086

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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: 9.00e-7

Gnomad4 OTH exome AF: 0.00

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

Labcorp Genetics (formerly Invitae), Labcorp

Oct 12, 2016

In summary, this variant is a novel missense change that is not predicted to affect protein function. There is no indication that it causes disease, but the available evidence is currently insufficient to prove that conclusively. 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. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a SMARCB1-related disease. This sequence change replaces alanine with valine at codon 238 of the SMARCB1 protein (p.Ala238Val). The alanine residue is highly conserved and there is a small physicochemical difference between alanine and valine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.46
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	0.040
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.39	.;T;T;.
Eigen	Benign	0.050
Eigen_PC	Benign	0.21
FATHMM_MKL	Uncertain	0.95	D
M_CAP	Benign	0.022	T
MetaRNN	Uncertain	0.68	D;D;D;D
MetaSVM	Benign	-0.63	T
MutationAssessor	Benign	1.1	.;L;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Benign	-1.8	N;.;N;.
REVEL	Uncertain	0.44
Sift	Benign	0.50	T;.;T;.
Sift4G	Benign	0.29	T;.;T;.
Polyphen		0.026, 0.0080	.;B;B;.
Vest4		0.74
MutPred		0.65		.;.;Loss of disorder (P = 0.1441);.;
MVP		0.74
MPC		1.4
ClinPred		0.57	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.49
gMVP		0.89

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1060503019; hg19: chr22-24159041;