rs863225458

Variant names:

• chrX-53396232-CCTGA-C
• rs863225458
• NM_006306.4:c.2853_2856delTCAG

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_006306.4(SMC1A):​c.2853_2856delTCAG​(p.Ser951ArgfsTer12) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 22)
• Consequence: SMC1A NM_006306.4 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 7.67
• Publications: 6 publications found

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]

SMC1A Gene-Disease associations (from GenCC):

• Cornelia de Lange syndrome 2

  Inheritance: XL Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• developmental and epileptic encephalopathy, 85, with or without midline brain defects

  Inheritance: XL Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• X-linked complex neurodevelopmental disorder

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen
• atypical Rett syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Cornelia de Lange syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-53396232-CCTGA-C is Pathogenic according to our data. Variant chrX-53396232-CCTGA-C is described in ClinVar as Pathogenic. ClinVar VariationId is 208626.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006306.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMC1A	NM_006306.4	MANE Select	c.2853_2856delTCAG	p.Ser951ArgfsTer12	frameshift	Exon 18 of 25	NP_006297.2
	SMC1A	NM_001281463.1		c.2787_2790delTCAG	p.Ser929ArgfsTer12	frameshift	Exon 19 of 26	NP_001268392.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMC1A	ENST00000322213.9	TSL:1 MANE Select	c.2853_2856delTCAG	p.Ser951ArgfsTer12	frameshift	Exon 18 of 25	ENSP00000323421.3
	SMC1A	ENST00000375340.10	TSL:1	c.2787_2790delTCAG	p.Ser929ArgfsTer12	frameshift	Exon 19 of 26	ENSP00000364489.7
	SMC1A	ENST00000675504.1		c.2787_2790delTCAG	p.Ser929ArgfsTer12	frameshift	Exon 18 of 25	ENSP00000502524.1

Frequencies

GnomAD3 genomes Cov.: 22

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 22

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
2	-	-	Congenital muscular hypertrophy-cerebral syndrome (2)
1	-	-	Developmental and epileptic encephalopathy, 85, with or without midline brain defects (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.7
Mutation Taster		=1/199	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs863225458; hg19: chrX-53423152;