18-47841913-G-A

Position:

• chr18-47841913-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP2

The NM_005901.6(SMAD2):​c.1318C>T​(p.Leu440Phe) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SMAD2 NM_005901.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.74

Genes affected

SMAD2 (HGNC:6768): (SMAD family member 2) The protein encoded by this gene belongs to the SMAD, a family of proteins similar to the gene products of the Drosophila gene 'mothers against decapentaplegic' (Mad) and the C. elegans gene Sma. SMAD proteins are signal transducers and transcriptional modulators that mediate multiple signaling pathways. This protein mediates the signal of the transforming growth factor (TGF)-beta, and thus regulates multiple cellular processes, such as cell proliferation, apoptosis, and differentiation. This protein is recruited to the TGF-beta receptors through its interaction with the SMAD anchor for receptor activation (SARA) protein. In response to TGF-beta signal, this protein is phosphorylated by the TGF-beta receptors. The phosphorylation induces the dissociation of this protein with SARA and the association with the family member SMAD4. The association with SMAD4 is important for the translocation of this protein into the nucleus, where it binds to target promoters and forms a transcription repressor complex with other cofactors. This protein can also be phosphorylated by activin type 1 receptor kinase, and mediates the signal from the activin. Alternatively spliced transcript variants have been observed for this gene. [provided by RefSeq, May 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_005901.6
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SMAD2. . Gene score misZ 3.6626 (greater than the threshold 3.09). Trascript score misZ 4.4705 (greater than threshold 3.09). GenCC has associacion of gene with Loeys-Dietz syndrome 6, congenital heart disease, familial thoracic aortic aneurysm and aortic dissection, Loeys-Dietz syndrome, congenital heart defects, multiple types, 8, with or without heterotaxy.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMAD2	NM_005901.6	c.1318C>T	p.Leu440Phe	missense_variant	11/11	ENST00000262160.11
SMAD2	NM_001003652.4	c.1318C>T	p.Leu440Phe	missense_variant	11/11
SMAD2	NM_001135937.3	c.1228C>T	p.Leu410Phe	missense_variant	10/10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMAD2	ENST00000262160.11	c.1318C>T	p.Leu440Phe	missense_variant	11/11	1	NM_005901.6
SMAD2	ENST00000402690.6	c.1318C>T	p.Leu440Phe	missense_variant	11/11	1
SMAD2	ENST00000356825.8	c.1228C>T	p.Leu410Phe	missense_variant	10/10	1		P1
SMAD2	ENST00000586040.5	c.1228C>T	p.Leu410Phe	missense_variant	9/9	5		P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

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

Apr 07, 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 SMAD2 protein function. This variant has not been reported in the literature in individuals affected with SMAD2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces leucine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 440 of the SMAD2 protein (p.Leu440Phe). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.38
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D;D;.;.
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.58
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	.;D;D;.
M_CAP	Uncertain	0.25	D
MetaRNN	Uncertain	0.72	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.2	M;M;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Uncertain	-3.0	D;D;D;.
REVEL	Pathogenic	0.78
Sift	Uncertain	0.0030	D;D;D;.
Sift4G	Uncertain	0.0030	D;D;D;D
Polyphen		0.19	B;B;D;D
Vest4		0.65
MutPred		0.68		Loss of stability (P = 0.1126);Loss of stability (P = 0.1126);.;.;
MVP		0.96
MPC		1.5
ClinPred		0.87	D
GERP RS		5.7
Varity_R		0.82
gMVP		0.97

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr18-45368284;