X-53374622-C-T

Variant names:

• chrX-53374622-C-T
• rs147896900
• NM_006306.4:c.*5481G>A

Variant summary

Our verdict is Benign. The variant received -12 ACMG points: 0P and 12B. BP4_Strong BA1

The NM_006306.4(SMC1A):​c.*5481G>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.016 in 111,655 control chromosomes in the GnomAD database, including 24 homozygotes. There are 430 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: 𝑓 0.016 (24 hom., 430 hem., cov: 23)
  • Exomes 𝑓: 0.0 (0 hom. 0 hem.)
  • Failed GnomAD Quality Control
• Consequence: SMC1A NM_006306.4 3_prime_UTR
• Clinical Significance: Benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.0120
• Publications: 0 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 -12 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.82).
• BA1: GnomAd4 highest subpopulation (AFR) allele frequency at 95% confidence interval = 0.0531 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMC1A	NM_006306.4	c.*5481G>A		3_prime_UTR_variant	Exon 25 of 25	ENST00000322213.9	NP_006297.2
SMC1A	NM_001281463.1	c.*5481G>A		3_prime_UTR_variant	Exon 26 of 26		NP_001268392.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMC1A	ENST00000322213.9	c.*5481G>A		3_prime_UTR_variant	Exon 25 of 25	1	NM_006306.4	ENSP00000323421.3
SMC1A	ENST00000375340.10	c.*5481G>A		3_prime_UTR_variant	Exon 26 of 26	1		ENSP00000364489.7
SMC1A	ENST00000675504.1	c.*5481G>A		3_prime_UTR_variant	Exon 25 of 25			ENSP00000502524.1

Frequencies

GnomAD3 genomes AF: 0.0160 AC: 1781 AN: 111603 Hom.: 24 Cov.: 23

Gnomad AFR AF: 0.0553

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00581

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00112

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000940

Gnomad OTH AF: 0.0120

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 412 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 160

African (AFR) AF: 0.00 AC: 0 AN: 5

American (AMR) AC: 0 AN: 0

Ashkenazi Jewish (ASJ) AC: 0 AN: 0

East Asian (EAS) AC: 0 AN: 0

South Asian (SAS) AC: 0 AN: 0

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 363

Middle Eastern (MID) AC: 0 AN: 0

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 40

Other (OTH) AF: 0.00 AC: 0 AN: 4

GnomAD4 genome AF: 0.0160 AC: 1782 AN: 111655 Hom.: 24 Cov.: 23 AF XY: 0.0127 AC XY: 430 AN XY: 33833

African (AFR) AF: 0.0552 AC: 1695 AN: 30683

American (AMR) AF: 0.00580 AC: 61 AN: 10512

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 2645

East Asian (EAS) AF: 0.00 AC: 0 AN: 3556

South Asian (SAS) AF: 0.00113 AC: 3 AN: 2663

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 6016

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 219

European-Non Finnish (NFE) AF: 0.0000941 AC: 5 AN: 53161

Other (OTH) AF: 0.0118 AC: 18 AN: 1520

Alfa AF: 0.00810 Hom.: 36

Bravo AF: 0.0198

ClinVar

Significance: Benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital muscular hypertrophy-cerebral syndrome Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.82
CADD	Benign	1.4
DANN	Benign	0.64
PhyloP100		0.012
Mutation Taster		=100/0	polymorphism (auto)

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: rs147896900; hg19: chrX-53401543;