chr15-66781042-G-C

Variant names:

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_ModerateBP6BS1

The NM_005585.5(SMAD6):c.998G>C(p.Ser333Thr) variant causes a missense change. The variant allele was found at a frequency of 0.000196 in 1,600,588 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. S333N) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00018 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00020 ( 0 hom. )

Consequence

SMAD6
NM_005585.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:1

Conservation

PhyloP100: 4.44

Publications

4 publications found

Variant links:

Genes affected

SMAD6 (HGNC:6772): (SMAD family member 6) The protein encoded by this gene belongs to the SMAD family of proteins, which are related to Drosophila 'mothers against decapentaplegic' (Mad) and C. elegans Sma. SMAD proteins are signal transducers and transcriptional modulators that mediate multiple signaling pathways. This protein functions in the negative regulation of BMP and TGF-beta/activin-signalling. Multiple transcript variants have been found for this gene.[provided by RefSeq, Sep 2014]

SMAD6 Gene-Disease associations (from GenCC):

craniosynostosis 7
Inheritance: AD, Unknown Classification: STRONG, MODERATE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics, PanelApp Australia
radioulnar synostosis, nonsyndromic, susceptibility to
Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics
aortic valve disease 2
Inheritance: AD, Unknown Classification: MODERATE, LIMITED Submitted by: Ambry Genetics, PanelApp Australia, Labcorp Genetics (formerly Invitae)
familial bicuspid aortic valve
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
congenital radioulnar synostosis
Inheritance: AR, Unknown Classification: SUPPORTIVE, LIMITED Submitted by: Ambry Genetics, Orphanet
congenital heart defects, multiple types
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

SMAD6 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -7 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.08331406).

BP6

Variant 15-66781042-G-C is Benign according to our data. Variant chr15-66781042-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 471766.

BS1

Variant frequency is greater than expected in population nfe. GnomAdExome4 allele frequency = 0.000198 (287/1448226) while in subpopulation NFE AF = 0.000246 (273/1109828). AF 95% confidence interval is 0.000222. There are 0 homozygotes in GnomAdExome4. There are 125 alleles in the male GnomAdExome4 subpopulation. Median coverage is 34. This position passed quality control check.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMAD6	NM_005585.5 link	c.998G>C	p.Ser333Thr	missense_variant	Exon 4 of 4	ENST00000288840.10	NP_005576.3	O43541-1
SMAD6	XM_011521561.3 link	c.215G>C	p.Ser72Thr	missense_variant	Exon 4 of 4		XP_011519863.1	O43541-2
SMAD6	NR_027654.2 link	n.2153G>C		non_coding_transcript_exon_variant	Exon 5 of 5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMAD6	ENST00000288840.10 link	c.998G>C	p.Ser333Thr	missense_variant	Exon 4 of 4	1	NM_005585.5	ENSP00000288840.5		O43541-1

Frequencies

GnomAD3 genomes

AF:

0.000177

AC:

AN:

152244

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

Gnomad AMI

AF:

0.00439

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000279

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000104

AC:

AN:

229762

AF XY:

0.000103

show subpopulations

Gnomad AFR exome

AF:

0.0000690

Gnomad AMR exome

AF:

0.0000296

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000209

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000198

AC:

287

AN:

1448226

Hom.:

Cov.:

AF XY:

0.000174

AC XY:

125

AN XY:

720434

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33330

American (AMR)

AF:

0.000113

AC:

AN:

44338

Ashkenazi Jewish (ASJ)

AF:

0.0000384

AC:

AN:

26020

East Asian (EAS)

AF:

0.00

AC:

AN:

39394

South Asian (SAS)

AF:

0.00

AC:

AN:

85298

European-Finnish (FIN)

AF:

0.00

AC:

AN:

44156

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.000246

AC:

273

AN:

1109828

Other (OTH)

AF:

0.000133

AC:

AN:

60096

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.484

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000177

AC:

AN:

152362

Hom.:

Cov.:

AF XY:

0.000121

AC XY:

AN XY:

74502

show subpopulations

African (AFR)

AF:

0.0000481

AC:

AN:

41584

American (AMR)

AF:

0.000131

AC:

AN:

15310

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000279

AC:

AN:

68038

Other (OTH)

AF:

0.00

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.481

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000248

Hom.:

Bravo

AF:

0.000238

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000909

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Mar 30, 2021

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis supports that this missense variant does not alter protein structure/function; Identified in a patient with craniosynostosis in published literature; however, the variant did not appear to negatively affect SMAD6 inhibitory function on luciferase assay (Calpena et al., 2020); This variant is associated with the following publications: (PMID: 32499606) -

Aortic valve disease 2

Uncertain:1

Jan 12, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces serine, which is neutral and polar, with threonine, which is neutral and polar, at codon 333 of the SMAD6 protein (p.Ser333Thr). This variant is present in population databases (rs199531653, gnomAD 0.02%). This missense change has been observed in individual(s) with craniosynostosis (PMID: 32499606). ClinVar contains an entry for this variant (Variation ID: 471766). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt SMAD6 protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change does not substantially affect SMAD6 function (PMID: 32499606). 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 specified

Benign:1

Mar 31, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: SMAD6 c.998G>C (p.Ser333Thr) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0001 in 229762 control chromosomes. The observed variant frequency is approximately 3.34 fold of the estimated maximal expected allele frequency for a pathogenic variant in SMAD6 causing Aortic Valve Disease phenotype (3.1e-05). c.998G>C has been reported in the literature in individuals affected with Aortic Valve Disease. These report(s) do not provide unequivocal conclusions about association of the variant with Aortic Valve Disease. At least one publication reports experimental evidence evaluating an impact on protein function, however, does not allow convincing conclusions about the variant effect. ClinVar contains an entry for this variant (Variation ID: 471766). Based on the evidence outlined above, the variant was classified as likely benign. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Benign

-0.037

BayesDel_noAF

Uncertain

-0.010

CADD

Uncertain

(source)

DANN

Benign

0.91

DEOGEN2

Uncertain

0.68

Eigen

Benign

0.017

Eigen_PC

Benign

0.20

FATHMM_MKL

Uncertain

0.80

LIST_S2

Benign

0.76

M_CAP

Uncertain

0.090

MetaRNN

Benign

0.083

MetaSVM

Uncertain

0.55

MutationAssessor

Benign

1.3

PhyloP100

4.4

PrimateAI

Uncertain

0.57

PROVEAN

Benign

-0.83

REVEL

Uncertain

0.40

Sift

Benign

0.37

Sift4G

Benign

0.64

Polyphen

0.014

Vest4

0.29

MVP

0.79

MPC

0.27

ClinPred

0.041

GERP RS

4.6

Varity_R

0.22

gMVP

0.30

Mutation Taster

=75/25

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over