rs633422

Variant summary

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

The NM_015295.3(SMCHD1):​c.2637A>C​(p.Lys879Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000384 in 1,588,792 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Benign in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K879E) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 31)
Exomes 𝑓: 0.000039 ( 0 hom. )

Consequence

SMCHD1
NM_015295.3 missense

Scores

1
18

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 1.03

Publications

35 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

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=0.041606873).
BS1
Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.0000329 (5/152014) while in subpopulation SAS AF = 0.00104 (5/4822). AF 95% confidence interval is 0.000408. There are 0 homozygotes in GnomAd4. There are 4 alleles in the male GnomAd4 subpopulation. Median coverage is 31. 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 5 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
SMCHD1NM_015295.3 linkc.2637A>C p.Lys879Asn missense_variant Exon 21 of 48 ENST00000320876.11 NP_056110.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
SMCHD1ENST00000320876.11 linkc.2637A>C p.Lys879Asn missense_variant Exon 21 of 48 5 NM_015295.3 ENSP00000326603.7 A6NHR9-1

Frequencies

GnomAD3 genomes
AF:
0.0000329
AC:
5
AN:
151896
Hom.:
0
Cov.:
31
show subpopulations
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:
0.00104
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000617
AC:
14
AN:
226952
AF XY:
0.0000817
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000390
AC:
56
AN:
1436778
Hom.:
0
Cov.:
31
AF XY:
0.0000575
AC XY:
41
AN XY:
713346
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33220
American (AMR)
AF:
0.00
AC:
0
AN:
42594
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25546
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39294
South Asian (SAS)
AF:
0.000628
AC:
52
AN:
82768
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
51910
Middle Eastern (MID)
AF:
0.000175
AC:
1
AN:
5700
European-Non Finnish (NFE)
AF:
9.12e-7
AC:
1
AN:
1096496
Other (OTH)
AF:
0.0000338
AC:
2
AN:
59250
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.469
Heterozygous variant carriers
0
3
6
8
11
14
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
0.0000329
AC:
5
AN:
152014
Hom.:
0
Cov.:
31
AF XY:
0.0000538
AC XY:
4
AN XY:
74304
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41544
American (AMR)
AF:
0.00
AC:
0
AN:
15268
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5170
South Asian (SAS)
AF:
0.00104
AC:
5
AN:
4822
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10568
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
292
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
67862
Other (OTH)
AF:
0.00
AC:
0
AN:
2110
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.575
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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:
0.00
Hom.:
9480
ExAC
AF:
0.0000748
AC:
9

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Uncertain:2
Sep 09, 2019
Revvity Omics, Revvity
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Sep 11, 2015
Eurofins Ntd Llc (ga)
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Facioscapulohumeral muscular dystrophy 2 Uncertain:1
Nov 19, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces lysine, which is basic and polar, with asparagine, which is neutral and polar, at codon 879 of the SMCHD1 protein (p.Lys879Asn). This variant is present in population databases (rs633422, gnomAD 0.05%). 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: 283266). 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. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.20
BayesDel_addAF
Benign
-0.51
T
BayesDel_noAF
Benign
-0.63
CADD
Benign
16
DANN
Benign
0.97
DEOGEN2
Benign
0.086
T
Eigen
Benign
-0.38
Eigen_PC
Benign
-0.21
FATHMM_MKL
Uncertain
0.85
D
LIST_S2
Benign
0.53
T
M_CAP
Benign
0.0053
T
MetaRNN
Benign
0.042
T
MetaSVM
Benign
-1.1
T
MutationAssessor
Benign
1.2
L
PhyloP100
1.0
PrimateAI
Benign
0.41
T
PROVEAN
Benign
-0.65
N
REVEL
Benign
0.099
Sift
Benign
0.34
T
Sift4G
Benign
0.22
T
Polyphen
0.0
B
Vest4
0.040
MutPred
0.11
Loss of methylation at K879 (P = 0.0135);
MVP
0.068
MPC
0.25
ClinPred
0.046
T
GERP RS
3.1
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.069
gMVP
0.37
Mutation Taster
=97/3
polymorphism

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

Other links and lift over

dbSNP: rs633422; hg19: chr18-2724930; API