chr18-2724932-A-C

Position:

chr18-2724932-A-C

Variant summary

Our verdict is Benign. Variant got -8 ACMG points: 1P and 9B. PP2BP4_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. 15/21 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 Lovd.

Frequency

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

Exomes 𝑓: 0.000039 ( 0 hom. )

Consequence

SMCHD1
NM_015295.3 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 1.03

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 links:

ENSG00000266049 (HGNC:):

ENSG00000266049 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -8 ACMG points.

PP2

Missense variant in the SMCHD1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 23 curated pathogenic missense variants (we use a threshold of 10). The gene has 10 curated benign missense variants. Gene score misZ: 3.6318 (above the threshold of 3.09). Trascript score misZ: 3.965 (above the threshold of 3.09). GenCC associations: The gene is linked to facioscapulohumeral muscular dystrophy, arhinia, choanal atresia, and microphthalmia, hyposmia-nasal and ocular hypoplasia-hypogonadotropic hypogonadism syndrome.

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 male gnomad4 subpopulation. Median coverage is 31. This position pass quality control queck. 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/exons	MANE	Protein	UniProt
SMCHD1	NM_015295.3 link	c.2637A>C	p.Lys879Asn	missense_variant	21/48	ENST00000320876.11	NP_056110.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SMCHD1	ENST00000320876.11 link	c.2637A>C	p.Lys879Asn	missense_variant	21/48	5	NM_015295.3	ENSP00000326603.7		A6NHR9-1

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

151896

Hom.:

Cov.:

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

GnomAD3 exomes

AF:

0.0000617

AC:

AN:

226952

Hom.:

AF XY:

0.0000817

AC XY:

AN XY:

122364

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 SAS exome

AF:

0.000498

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000390

AC:

AN:

1436778

Hom.:

Cov.:

AF XY:

0.0000575

AC XY:

AN XY:

713346

show subpopulations

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:

0.000628

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

9.12e-7

Gnomad4 OTH exome

AF:

0.0000338

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152014

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74304

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00104

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

ExAC

AF:

0.0000748

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Sep 09, 2019	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Sep 11, 2015	- -

Facioscapulohumeral muscular dystrophy 2

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 19, 2024

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

BayesDel_noAF

Benign

-0.63

CADD

Benign

DANN

Benign

0.97

DEOGEN2

Benign

0.086

Eigen

Benign

-0.38

Eigen_PC

Benign

-0.21

FATHMM_MKL

Uncertain

0.85

LIST_S2

Benign

0.53

M_CAP

Benign

0.0053

MetaRNN

Benign

0.042

MetaSVM

Benign

-1.1

MutationAssessor

Benign

1.2

PrimateAI

Benign

0.41

PROVEAN

Benign

-0.65

REVEL

Benign

0.099

Sift

Benign

0.34

Sift4G

Benign

0.22

Polyphen

0.0

Vest4

0.040

MutPred

0.11

Loss of methylation at K879 (P = 0.0135);

MVP

0.068

MPC

0.25

ClinPred

0.046

GERP RS

3.1

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.069

gMVP

0.37

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over