chrX-53381075-G-T

Variant names:

• chrX-53381075-G-T
• rs142611198
• NM_006306.4:c.3450C>A

Variant summary

Our verdict is Benign. The variant received -17 ACMG points: 0P and 17B. BP4_Strong BP6_Very_Strong BP7 BS2

The NM_006306.4(SMC1A):​c.3450C>A​(p.Ala1150Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000183 in 1,094,608 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 7 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. A1150A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 22)
  • Exomes 𝑓: 0.000018 (0 hom. 7 hem.)
• Consequence: SMC1A NM_006306.4 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:2
• Conservation: PhyloP100: -0.326
• Publications: 2 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: Benign. The variant received -17 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.61).
• BP6: Variant X-53381075-G-T is Benign according to our data. Variant chrX-53381075-G-T is described in ClinVar as Likely_benign. ClinVar VariationId is 1609877.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-0.326 with no splicing effect.
• BS2: High AC in GnomAdExome4 at 20 AD,XL gene.

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.3450C>A	p.Ala1150Ala	synonymous	Exon 23 of 25	NP_006297.2
	SMC1A	NM_001281463.1		c.3384C>A	p.Ala1128Ala	synonymous	Exon 24 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.3450C>A	p.Ala1150Ala	synonymous	Exon 23 of 25	ENSP00000323421.3
	SMC1A	ENST00000375340.10	TSL:1	c.3384C>A	p.Ala1128Ala	synonymous	Exon 24 of 26	ENSP00000364489.7
	SMC1A	ENST00000675504.1		c.3384C>A	p.Ala1128Ala	synonymous	Exon 23 of 25	ENSP00000502524.1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD2 exomes AF: 0.0000109 AC: 2 AN: 183171 AF XY: 0.0000148

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000245

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000183 AC: 20 AN: 1094608 Hom.: 0 Cov.: 30 AF XY: 0.0000194 AC XY: 7 AN XY: 360046

African (AFR) AF: 0.00 AC: 0 AN: 26335

American (AMR) AF: 0.00 AC: 0 AN: 35192

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 19360

East Asian (EAS) AF: 0.00 AC: 0 AN: 30191

South Asian (SAS) AF: 0.00 AC: 0 AN: 54034

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 40526

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4124

European-Non Finnish (NFE) AF: 0.0000226 AC: 19 AN: 838879

Other (OTH) AF: 0.0000218 AC: 1 AN: 45967

GnomAD4 genome Cov.: 22

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital muscular hypertrophy-cerebral syndrome Benign:1

Feb 14, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Congenital muscular hypertrophy-cerebral syndrome;C5393312:Developmental and epileptic encephalopathy, 85, with or without midline brain defects Benign:1

Oct 20, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.61
CADD	Benign	6.3
DANN	Benign	0.62
PhyloP100		-0.33
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=84/16	polymorphism

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: rs142611198; hg19: chrX-53407996;