15-66781449-G-C

Position:

• chr15-66781449-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_005585.5(SMAD6):​c.1405G>C​(p.Ala469Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000688 in 1,452,760 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. A469T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (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 8 ACMG points.

• PM1: In a domain MH2 (size 165) in uniprot entity SMAD6_HUMAN there are 15 pathogenic changes around while only 6 benign (71%) in NM_005585.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.978

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMAD6	NM_005585.5	c.1405G>C	p.Ala469Pro	missense_variant	4/4	ENST00000288840.10
SMAD6	XM_011521561.3	c.622G>C	p.Ala208Pro	missense_variant	4/4
SMAD6	NR_027654.2	n.2560G>C		non_coding_transcript_exon_variant	5/5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMAD6	ENST00000288840.10	c.1405G>C	p.Ala469Pro	missense_variant	4/4	1	NM_005585.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.88e-7 AC: 1 AN: 1452760 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 722842

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: 9.01e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Aortic valve disease 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 03, 2017

This variant has not been reported in the literature in individuals with SMAD6-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency). This sequence change replaces alanine with proline at codon 469 of the SMAD6 protein (p.Ala469Pro). The alanine residue is highly conserved and there is a small physicochemical difference between alanine and proline. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D
M_CAP	Uncertain	0.26	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.6	M
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.87	D
PROVEAN	Uncertain	-3.9	D
REVEL	Pathogenic	0.97
Sift	Uncertain	0.0050	D
Sift4G	Uncertain	0.0050	D
Polyphen		1.0	D
Vest4		0.93
MutPred		0.87		Loss of stability (P = 0.0394);
MVP		0.95
MPC		1.0
ClinPred		0.99	D
GERP RS		5.7
Varity_R		0.97
gMVP		0.87

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: rs1416212959; hg19: chr15-67073787;