rs587784408

Variant names:

• chrX-53405130-C-T
• rs587784408
• NM_006306.4:c.2078G>A

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP2 PP3 PP5_Very_Strong

The NM_006306.4(SMC1A):​c.2078G>A​(p.Arg693Gln) 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. R693G) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 24)
  • Exomes 𝑓: 0.0 (0 hom. 0 hem.)
  • Failed GnomAD Quality Control
• Consequence: SMC1A NM_006306.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.80

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 16 ACMG points.

• PM1: In a coiled_coil_region (size 275) in uniprot entity SMC1A_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_006306.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP2: Missense variant in the SMC1A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 68 curated pathogenic missense variants (we use a threshold of 10). The gene has 31 curated benign missense variants. Gene score misZ: 6.4479 (above the threshold of 3.09). GenCC associations: The gene is linked to Cornelia de Lange syndrome, X-linked complex neurodevelopmental disorder, atypical Rett syndrome, Cornelia de Lange syndrome 2, developmental and epileptic encephalopathy, 85, with or without midline brain defects.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.807
• PP5: Variant X-53405130-C-T is Pathogenic according to our data. Variant chrX-53405130-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 159946.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chrX-53405130-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMC1A	NM_006306.4	c.2078G>A	p.Arg693Gln	missense_variant	Exon 13 of 25	ENST00000322213.9	NP_006297.2
SMC1A	NM_001281463.1	c.2012G>A	p.Arg671Gln	missense_variant	Exon 14 of 26		NP_001268392.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMC1A	ENST00000322213.9	c.2078G>A	p.Arg693Gln	missense_variant	Exon 13 of 25	1	NM_006306.4	ENSP00000323421.3

Frequencies

GnomAD3 genomes Cov.: 24

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1097504 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 362892

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 24

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital muscular hypertrophy-cerebral syndrome Pathogenic:2

Mar 23, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt SMC1A protein function. For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg693 amino acid residue in SMC1A. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 19701948). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 159946). This missense change has been observed in individual(s) with Cornelia de Lange syndrome (PMID: 24124034). In at least one individual the variant was observed to be de novo. It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 693 of the SMC1A protein (p.Arg693Gln). -

Feb 08, 2013

Genetic Services Laboratory, University of Chicago

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Jan 22, 2025

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Missense variants in this gene are a common cause of disease and they are underrepresented in the general population; This variant is associated with the following publications: (PMID: 24124034, 36246631, 37377026) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.080
CADD	Uncertain	26
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.48	T;T
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.81	D;D
MetaSVM	Pathogenic	0.83	D
MutationAssessor	Uncertain	2.3	M;.
PrimateAI	Pathogenic	0.80	D
PROVEAN	Uncertain	-3.8	D;.
REVEL	Pathogenic	0.78
Sift	Pathogenic	0.0	D;.
Sift4G	Uncertain	0.0060	D;D
Polyphen		1.0	D;.
Vest4		0.54
MutPred		0.61		Gain of ubiquitination at K690 (P = 0.0497);.;
MVP		0.93
MPC		3.0
ClinPred		1.0	D
GERP RS		5.3
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.7
Varity_R		0.91
gMVP		0.91

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: rs587784408; hg19: chrX-53432062; COSMIC: COSV100447775; COSMIC: COSV100447775;