rs878854233

Positions:

• chr19-11060117-G-A
• chr19-11060117-G-C
• chr19-11060117-G-T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 1P and 6B. PP2 BP4_Moderate BS2

The NM_001387283.1(SMARCA4):​c.4937G>A​(p.Arg1646Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000005 in 1,398,706 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1646W) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000050 (0 hom.)
• Consequence: SMARCA4 NM_001387283.1 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 2.60

Genes affected

SMARCA4 (HGNC:11100): (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a, member 4) The protein encoded by this gene is a member of the SWI/SNF family of proteins and is similar to the brahma protein of Drosophila. Members of this family have helicase and ATPase activities and are thought to regulate transcription of certain genes by altering the chromatin structure around those genes. The encoded protein is part of the large ATP-dependent chromatin remodeling complex SNF/SWI, which is required for transcriptional activation of genes normally repressed by chromatin. In addition, this protein can bind BRCA1, as well as regulate the expression of the tumorigenic protein CD44. Mutations in this gene cause rhabdoid tumor predisposition syndrome type 2. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2012]

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• PP2: Missense variant where missense usually causes diseases, SMARCA4
• BP4: Computational evidence support a benign effect (MetaRNN=0.25449538).
• BS2: High AC in GnomAdExome4 at 7 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMARCA4	NM_001387283.1	c.4937G>A	p.Arg1646Gln	missense_variant	35/36	ENST00000646693.2
SMARCA4	NM_003072.5	c.4841G>A	p.Arg1614Gln	missense_variant	34/35	ENST00000344626.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMARCA4	ENST00000646693.2	c.4937G>A	p.Arg1646Gln	missense_variant	35/36		NM_001387283.1
SMARCA4	ENST00000344626.10	c.4841G>A	p.Arg1614Gln	missense_variant	34/35	1	NM_003072.5	P4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000500 AC: 7 AN: 1398706 Hom.: 0 Cov.: 33 AF XY: 0.00000435 AC XY: 3 AN XY: 689916

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000397

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000252

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000371

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Rhabdoid tumor predisposition syndrome 2 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	May 04, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Jan 21, 2024	This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 1646 of the SMARCA4 protein (p.Arg1646Gln). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SMARCA4-related conditions. ClinVar contains an entry for this variant (Variation ID: 238494). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on SMARCA4 protein function. 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Apr 17, 2023

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Hereditary cancer-predisposing syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 15, 2023

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Uncertain	0.020	T
BayesDel_noAF	Benign	-0.21
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.48	T;.;T;.;.;.;.;.;.;.;T;.;.;.;.;.;T;T;.;.;.;.
Eigen	Benign	0.11
Eigen_PC	Benign	0.15
FATHMM_MKL	Uncertain	0.93	D
M_CAP	Uncertain	0.24	D
MetaRNN	Benign	0.25	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.018	T
MutationAssessor	Benign	0.90	L;.;.;.;.;.;.;.;.;.;L;.;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	0.83	D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.59	T
PROVEAN	Benign	-1.2	N;.;.;.;.;.;.;.;.;.;N;.;.;.;N;.;.;.;.;.;.;.
REVEL	Uncertain	0.33
Sift	Uncertain	0.011	D;.;.;.;.;.;.;.;.;.;D;.;.;.;D;.;.;.;.;.;.;.
Sift4G	Benign	0.21	T;.;.;.;.;.;.;.;.;.;T;.;T;T;T;T;T;T;.;.;.;.
Polyphen		0.97	D;.;P;.;.;.;.;.;.;.;D;.;.;.;.;.;.;P;.;.;.;.
Vest4		0.22
MutPred		0.28		.;.;Loss of methylation at R1646 (P = 0.0306);.;.;.;.;.;.;.;.;.;.;.;.;.;.;Loss of methylation at R1646 (P = 0.0306);.;.;.;.;
MVP		0.68
MPC		1.4
ClinPred		0.81	D
GERP RS		3.5
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.7
Varity_R		0.20
gMVP		0.64

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: rs878854233; hg19: chr19-11170793;