rs587784407

Variant names:

• chrX-53405527-C-T
• rs587784407
• NM_006306.4:c.1877G>A

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2 PP2 PP5_Very_Strong

The NM_006306.4(SMC1A):​c.1877G>A​(p.Arg626His) variant causes a missense change. The variant allele was found at a frequency of 0.000000911 in 1,098,146 control chromosomes in the GnomAD database, with no homozygous occurrence. There are no hemizygote samples in GnomAD. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 9.1e-7 (0 hom. 0 hem.)
• Consequence: SMC1A NM_006306.4 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 3.98

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]

MIR6857 (HGNC:50263): (microRNA 6857) microRNAs (miRNAs) are short (20-24 nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. miRNAs are transcribed by RNA polymerase II as part of capped and polyadenylated primary transcripts (pri-miRNAs) that can be either protein-coding or non-coding. The primary transcript is cleaved by the Drosha ribonuclease III enzyme to produce an approximately 70-nt stem-loop precursor miRNA (pre-miRNA), which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA and antisense miRNA star (miRNA*) products. The mature miRNA is incorporated into a RNA-induced silencing complex (RISC), which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. The RefSeq represents the predicted microRNA stem-loop. [provided by RefSeq, Sep 2009]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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.
• PP5: Variant X-53405527-C-T is Pathogenic according to our data. Variant chrX-53405527-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 159945.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMC1A	NM_006306.4	c.1877G>A	p.Arg626His	missense_variant	Exon 11 of 25	ENST00000322213.9	NP_006297.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMC1A	ENST00000322213.9	c.1877G>A	p.Arg626His	missense_variant	Exon 11 of 25	1	NM_006306.4	ENSP00000323421.3

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 9.11e-7 AC: 1 AN: 1098146 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 363502

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: 0.00000119

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital muscular hypertrophy-cerebral syndrome Pathogenic:2

Sep 05, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 626 of the SMC1A protein (p.Arg626His). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of Cornelia de Lange syndrome (internal data). ClinVar contains an entry for this variant (Variation ID: 159945). 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 expected to disrupt SMC1A protein function with a positive predictive value of 80%. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Oct 07, 2013

Genetic Services Laboratory, University of Chicago

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.16
CADD	Pathogenic	27
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.56	D;T
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.80	D
MetaRNN	Uncertain	0.66	D;D
MetaSVM	Pathogenic	0.85	D
MutationAssessor	Pathogenic	3.2	M;.
PrimateAI	Pathogenic	0.87	D
PROVEAN	Uncertain	-3.1	D;.
REVEL	Pathogenic	0.76
Sift	Uncertain	0.013	D;.
Sift4G	Uncertain	0.018	D;D
Polyphen		1.0	D;.
Vest4		0.41
MutPred		0.59		Loss of solvent accessibility (P = 0.0299);.;
MVP		0.95
MPC		3.1
ClinPred		0.99	D
GERP RS		5.5
RBP_binding_hub_radar		0.97
RBP_regulation_power_radar		2.8
Varity_R		0.64
gMVP		0.96

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

Other links and lift over

dbSNP: rs587784407; hg19: chrX-53432459; COSMIC: COSV59128773; COSMIC: COSV59128773;