rs387906702

Positions:

• chrX-53403635-A-G

Variant summary

Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. PM1 PM2 PP2 PP3_Moderate PP5_Very_Strong

The NM_006306.4(SMC1A):​c.2351T>C​(p.Ile784Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I784V) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 22)
• Consequence: SMC1A NM_006306.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 8.90

Genes affected

SMC1A (HGNC:11111): (structural maintenance of chromosomes 1A) Proper cohesion of sister chromatids is a prerequisite for the correct segregation of chromosomes during cell division. The cohesin multiprotein complex is required for sister chromatid cohesion. This complex is composed partly of two structural maintenance of chromosomes (SMC) proteins, SMC3 and either SMC1B or the protein encoded by this gene. Most of the cohesin complexes dissociate from the chromosomes before mitosis, although those complexes at the kinetochore remain. Therefore, the encoded protein is thought to be an important part of functional kinetochores. In addition, this protein interacts with BRCA1 and is phosphorylated by ATM, indicating a potential role for this protein in DNA repair. This gene, which belongs to the SMC gene family, is located in an area of the X-chromosome that escapes X inactivation. Mutations in this gene result in Cornelia de Lange syndrome. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Jul 2013]

ACMG classification

Verdict is Pathogenic. Variant got 15 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_006306.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, SMC1A
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.854
• PP5: Variant X-53403635-A-G is Pathogenic according to our data. Variant chrX-53403635-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 29929.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chrX-53403635-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMC1A	NM_006306.4	c.2351T>C	p.Ile784Thr	missense_variant	15/25	ENST00000322213.9
SMC1A	NM_001281463.1	c.2285T>C	p.Ile762Thr	missense_variant	16/26

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMC1A	ENST00000322213.9	c.2351T>C	p.Ile784Thr	missense_variant	15/25	1	NM_006306.4	P1
SMC1A	ENST00000375340.10	c.2285T>C	p.Ile762Thr	missense_variant	16/26	1
SMC1A	ENST00000675504.1	c.2285T>C	p.Ile762Thr	missense_variant	15/25
SMC1A	ENST00000674590.1	c.1583T>C	p.Ile528Thr	missense_variant	13/23

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 22

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital muscular hypertrophy-cerebral syndrome Pathogenic:3

Pathogenic, no assertion criteria provided	literature only	OMIM	Aug 01, 2010	- -
Likely pathogenic, criteria provided, single submitter	literature only	Center for Human Genetics, University of Leuven	Jan 01, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	3billion	May 22, 2022	The variant is not observed in the gnomAD v2.1.1 dataset. Missense changes are a common disease-causing mechanism. In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.86; 3Cnet: 0.52). Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000029929). The variant has been observed in multiple (>3) similarly affected unrelated individuals (PMID: 20635401, 24124034, 24756084). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Dec 28, 2020	Not observed in large population cohorts (Lek et al., 2016); Missense variants in this gene are often considered pathogenic (Stenson et al., 2014); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 20635401, 24756084, 27159028, 24124034) -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Mar 01, 2019	- -

Inborn genetic diseases Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 24, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.71
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.44
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.53	D;T
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Pathogenic	0.76	D
MetaRNN	Pathogenic	0.85	D;D
MetaSVM	Uncertain	0.28	D
MutationAssessor	Benign	2.0	M;.
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-4.4	D;.
REVEL	Pathogenic	0.86
Sift	Uncertain	0.0010	D;.
Sift4G	Uncertain	0.0020	D;D
Polyphen		1.0	D;.
Vest4		0.81
MutPred		0.48		Gain of phosphorylation at I784 (P = 0.0137);.;
MVP		0.99
MPC		3.1
ClinPred		1.0	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.80
gMVP		0.90

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs387906702; hg19: chrX-53430567;