rs1555875915

Positions:

• chr22-23791835-AAG-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_003073.5(SMARCB1):​c.178_179del​(p.Arg60GlufsTer10) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. E58E) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: SMARCB1 NM_003073.5 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.70

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 Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 22-23791835-AAG-A is Pathogenic according to our data. Variant chr22-23791835-AAG-A is described in ClinVar as [Pathogenic]. Clinvar id is 486500.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMARCB1	NM_003073.5	c.178_179del	p.Arg60GlufsTer10	frameshift_variant	2/9	ENST00000644036.2
SMARCB1	NM_001007468.3	c.178_179del	p.Arg60GlufsTer9	frameshift_variant	2/9
SMARCB1	NM_001317946.2	c.178_179del	p.Arg60GlufsTer9	frameshift_variant	2/9
SMARCB1	NM_001362877.2	c.178_179del	p.Arg60GlufsTer10	frameshift_variant	2/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMARCB1	ENST00000644036.2	c.178_179del	p.Arg60GlufsTer10	frameshift_variant	2/9		NM_003073.5	A1

Frequencies

GnomAD3 genomes Cov.: 33

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 06, 2017

The c.178_179delAG pathogenic mutation, located in coding exon 2 of the SMARCB1 gene, results from a deletion of two nucleotides at nucleotide positions 178 to 179, causing a translational frameshift with a predicted alternate stop codon (p.R60Efs*10). A different deletion resulting in a stop codon at the same position (c.170_171delTG p.V57Gfs*13) has been identified in a patient with a central nervous system atypical teratoid rhabdoid tumor (AR/RT) at age 5 months (Kordes U et al. Genes Chromosomes Cancer, 2010 Feb;49:176-81). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

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: rs1555875915; hg19: chr22-24134022;