rs387907283

Positions:

• chr15-66781495-G-A
• chr15-66781495-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 8P and 1B. PM1 PM5 PP3_Strong BS2_Supporting

The NM_005585.5(SMAD6):​c.1451G>A​(p.Cys484Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000445 in 1,574,560 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C484F) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000042 (0 hom.)
• Consequence: SMAD6 NM_005585.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.87

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM1: In a domain MH2 (size 165) in uniprot entity SMAD6_HUMAN there are 9 pathogenic changes around while only 3 benign (75%) in NM_005585.5
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr15-66781495-G-T is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.968
• BS2: High AC in GnomAdExome4 at 6 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SMAD6	NM_005585.5	c.1451G>A	p.Cys484Tyr	missense_variant	4/4	ENST00000288840.10	NP_005576.3
SMAD6	XM_011521561.3	c.668G>A	p.Cys223Tyr	missense_variant	4/4		XP_011519863.1
SMAD6	NR_027654.2	n.2606G>A		non_coding_transcript_exon_variant	5/5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SMAD6	ENST00000288840.10	c.1451G>A	p.Cys484Tyr	missense_variant	4/4	1	NM_005585.5	ENSP00000288840	P1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152054 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000945

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000422 AC: 6 AN: 1422506 Hom.: 0 Cov.: 34 AF XY: 0.00000284 AC XY: 2 AN XY: 705074

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000548

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152054 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74266

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0000945

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

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

GeneDx

Nov 25, 2015

The C484Y variant in the SMAD6 gene has not been reported previously as a pathogenic variant, nor as a benign variant, to our knowledge. The C484Y variant was not observed in approximately 6400 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The C484Y variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species. In silico analysis predicts this variant is probably damaging to the protein structure/function. A missense variant in the same residue (C484F) has been reported in association with congenital cardiovascular malformation (Tan et al., 2012), supporting the functional importance of this region of the protein. We interpret C484Y as a variant of uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D
M_CAP	Uncertain	0.28	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	2.9	M
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-11	D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.81		Gain of sheet (P = 0.1945);
MVP		0.96
MPC		1.2
ClinPred		1.0	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.99
gMVP		0.84

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: rs387907283; hg19: chr15-67073833;