18-2747561-A-G

Variant names:

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_StrongBS1_SupportingBS2

The NM_015295.3(SMCHD1):c.3841A>G(p.Ile1281Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000269 in 1,608,970 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.00024 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00027 ( 0 hom. )

Consequence

SMCHD1
NM_015295.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 1.24

Publications

4 publications found

Variant links:

Genes affected

SMCHD1 (HGNC:29090): (structural maintenance of chromosomes flexible hinge domain containing 1) This gene encodes a protein which contains a hinge region domain found in members of the SMC (structural maintenance of chromosomes) protein family. [provided by RefSeq, Dec 2011]

SMCHD1 Gene-Disease associations (from GenCC):

arhinia, choanal atresia, and microphthalmia
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia, G2P, Ambry Genetics, ClinGen, Illumina
facioscapulohumeral muscular dystrophy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
hyposmia-nasal and ocular hypoplasia-hypogonadotropic hypogonadism syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

SMCHD1 links:

ENSG00000266049 (HGNC:):

ENSG00000266049 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -9 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.032705486).

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000236 (36/152284) while in subpopulation NFE AF = 0.000456 (31/68016). AF 95% confidence interval is 0.00033. There are 0 homozygotes in GnomAd4. There are 16 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

BS2

High AC in GnomAd4 at 36 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMCHD1	NM_015295.3 link	c.3841A>G	p.Ile1281Val	missense_variant	Exon 30 of 48	ENST00000320876.11	NP_056110.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMCHD1	ENST00000320876.11 link	c.3841A>G	p.Ile1281Val	missense_variant	Exon 30 of 48	5	NM_015295.3	ENSP00000326603.7		A6NHR9-1

Frequencies

GnomAD3 genomes

AF:

0.000237

AC:

AN:

152166

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

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:

0.000456

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000278

AC:

AN:

247856

AF XY:

0.000268

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000117

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000526

Gnomad OTH exome

AF:

0.000666

GnomAD4 exome

AF:

0.000273

AC:

397

AN:

1456686

Hom.:

Cov.:

AF XY:

0.000270

AC XY:

196

AN XY:

724850

show subpopulations

African (AFR)

AF:

0.000120

AC:

AN:

33310

American (AMR)

AF:

0.000134

AC:

AN:

44614

Ashkenazi Jewish (ASJ)

AF:

0.0000384

AC:

AN:

26052

East Asian (EAS)

AF:

0.00

AC:

AN:

39520

South Asian (SAS)

AF:

0.0000233

AC:

AN:

85956

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53302

Middle Eastern (MID)

AF:

0.000521

AC:

AN:

5754

European-Non Finnish (NFE)

AF:

0.000327

AC:

362

AN:

1107986

Other (OTH)

AF:

0.000316

AC:

AN:

60192

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.474

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

100

<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:

0.000236

AC:

AN:

152284

Hom.:

Cov.:

AF XY:

0.000215

AC XY:

AN XY:

74468

show subpopulations

African (AFR)

AF:

0.0000481

AC:

AN:

41560

American (AMR)

AF:

0.000196

AC:

AN:

15296

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:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000456

AC:

AN:

68016

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

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:

0.000505

Hom.:

Bravo

AF:

0.000246

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000492

AC:

ExAC

AF:

0.000257

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Nov 17, 2017

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

The SMCHD1 p.I1281V variant was not identified in the literature but was identified in dbSNP (ID: rs201059575) and ClinVar (classified as uncertain significance by EGL Genetic Diagnostics and Invitae). The variant was identified in control databases in 76 of 279258 chromosomes at a frequency of 0.0002721 (Genome Aggregation Database March 6, 2019, v2.1.1). The p.I1281 residue is not conserved in mammals and computational analyses (MUT Assesor, PolyPhen-2, SIFT, MutationTaster, Revel, FATHMM, MetaLR, DANN) do not suggest a high likelihood of impact to the protein; however this information is not predictive enough to rule out pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (Splice AI exome) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -

Facioscapulohumeral muscular dystrophy 2

Uncertain:1

Dec 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 1281 of the SMCHD1 protein (p.Ile1281Val). This variant is present in population databases (rs201059575, gnomAD 0.05%), and has an allele count higher than expected for a pathogenic variant. This variant has not been reported in the literature in individuals affected with SMCHD1-related conditions. ClinVar contains an entry for this variant (Variation ID: 282658). 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 SMCHD1 protein function with a negative predictive value of 80%. 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. -

Inborn genetic diseases

Uncertain:1

Jan 04, 2022

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.3841A>G (p.I1281V) alteration is located in exon 30 (coding exon 30) of the SMCHD1 gene. This alteration results from a A to G substitution at nucleotide position 3841, causing the isoleucine (I) at amino acid position 1281 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.080

BayesDel_addAF

Benign

-0.51

BayesDel_noAF

Benign

-0.63

CADD

Benign

(source)

DANN

Uncertain

0.98

DEOGEN2

Benign

0.11

Eigen

Benign

-0.48

Eigen_PC

Benign

-0.29

FATHMM_MKL

Benign

0.61

LIST_S2

Benign

0.77

M_CAP

Benign

0.0064

MetaRNN

Benign

0.033

MetaSVM

Benign

-1.0

MutationAssessor

Benign

0.90

PhyloP100

1.2

PrimateAI

Benign

0.28

PROVEAN

Benign

-0.63

REVEL

Benign

0.055

Sift

Uncertain

0.024

Sift4G

Uncertain

0.054

Polyphen

0.0

Vest4

0.13

MVP

0.043

MPC

0.18

ClinPred

0.029

GERP RS

3.6

Varity_R

0.047

gMVP

0.39

Mutation Taster

=98/2

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