Genetic Variant SMAD6:p.Ser333Ile (chr15-66781042-G-T) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_005585.5(SMAD6):c.998G>T(p.Ser333Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000069 in 1,448,228 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S333T) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

SMAD6
NM_005585.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 4.44

Publications

0 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:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMAD6	NM_005585.5 link	c.998G>T	p.Ser333Ile	missense_variant	Exon 4 of 4	ENST00000288840.10	NP_005576.3	O43541-1
SMAD6	XM_011521561.3 link	c.215G>T	p.Ser72Ile	missense_variant	Exon 4 of 4		XP_011519863.1	O43541-2
SMAD6	NR_027654.2 link	n.2153G>T		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>T	p.Ser333Ile	missense_variant	Exon 4 of 4	1	NM_005585.5	ENSP00000288840.5		O43541-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.90e-7

AC:

AN:

1448228

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

720434

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33330

American (AMR)

AF:

0.00

AC:

AN:

44338

Ashkenazi Jewish (ASJ)

AF:

0.00

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:

0.0000226

AC:

AN:

44156

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1109830

Other (OTH)

AF:

0.00

AC:

AN:

60096

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.225

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.51

BayesDel_addAF

Pathogenic

0.27

BayesDel_noAF

Pathogenic

0.14

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.91

Eigen

Uncertain

0.68

Eigen_PC

Uncertain

0.66

FATHMM_MKL

Uncertain

0.80

LIST_S2

Benign

0.78

M_CAP

Pathogenic

0.34

MetaRNN

Uncertain

0.65

MetaSVM

Pathogenic

1.0

MutationAssessor

Uncertain

2.7

PhyloP100

4.4

PrimateAI

Uncertain

0.61

PROVEAN

Uncertain

-2.5

REVEL

Pathogenic

0.76

Sift

Benign

0.10

Sift4G

Benign

0.20

Polyphen

0.86

Vest4

0.41

MutPred

0.67

Loss of disorder (P = 0.0272);

MVP

0.89

MPC

0.83

ClinPred

0.98

GERP RS

4.6

Varity_R

0.34

gMVP

0.56

Mutation Taster

=56/44

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

ClinVar

Computational scores

Splicing

Publications

Other links and lift over