22-23833568-G-T

Variant names:

• chr22-23833568-G-T
• rs745773662
• NM_003073.5:c.987-4G>T

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP6

The NM_003073.5(SMARCB1):​c.987-4G>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: SMARCB1 NM_003073.5 splice_region, intron
• Scores: Splicing: ADA: 0.00001992
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: -0.0130
• Publications: 0 publications found

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]

SMARCB1 Gene-Disease associations (from GenCC):

• Coffin-Siris syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• intellectual disability, autosomal dominant 15

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• rhabdoid tumor predisposition syndrome 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen
• SMARCB1-related schwannomatosis

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Ambry Genetics
• familial multiple meningioma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial rhabdoid tumor

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• schwannomatosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• complex neurodevelopmental disorder

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.8).
• BP6: Variant 22-23833568-G-T is Benign according to our data. Variant chr22-23833568-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1131822.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_003073.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMARCB1	NM_003073.5	MANE Select	c.987-4G>T		splice_region intron	N/A	NP_003064.2
	SMARCB1	NM_001362877.2		c.1041-4G>T		splice_region intron	N/A	NP_001349806.1
	SMARCB1	NM_001317946.2		c.1014-4G>T		splice_region intron	N/A	NP_001304875.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMARCB1	ENST00000644036.2	MANE Select	c.987-4G>T		splice_region intron	N/A	ENSP00000494049.2
	SMARCB1	ENST00000407422.8	TSL:1	c.960-4G>T		splice_region intron	N/A	ENSP00000383984.3
	SMARCB1	ENST00000263121.12	TSL:1	c.849-4G>T		splice_region intron	N/A	ENSP00000263121.8

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Aug 15, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.987-4G>T intronic variant results from a G to T substitution 4 nucleotides upstream from coding exon 8 in the SMARCB1 gene. This variant has been detected in multiple individuals with no reported features of Coffin-Siris syndrome (Ambry internal data). This nucleotide position is poorly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will result in the creation or strengthening of a novel splice acceptor site. RNA studies have demonstrated that this alteration results in an incomplete splice defect; the clinical impact of this abnormal splicing is unknown at this time (Ambry internal data). Based on the supporting evidence, the association of this alteration with rhabdoid tumor predisposition syndrome is unknown; however, the association of this alteration with Coffin-Siris syndrome is unlikely.

not provided Benign:1

Jul 24, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.80
CADD	Benign	8.4
DANN	Benign	0.86
PhyloP100		-0.013

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000020
dbscSNV1_RF	Benign	0.0
SpliceAI score (max)		0.53		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.53		Position offset: 24

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs745773662; hg19: chr22-24175755;