rs863225459

chrX-53380685-T-TGGCC

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_006306.4(SMC1A):c.3552_3553insGGCC(p.Ile1185GlyfsTer23) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 22)
• Consequence: SMC1A NM_006306.4 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 0.436

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 Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 5 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-53380685-T-TGGCC is Pathogenic according to our data. Variant chrX-53380685-T-TGGCC is described in ClinVar as [Pathogenic]. Clinvar id is 208627.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMC1A	NM_006306.4	c.3552_3553insGGCC	p.Ile1185GlyfsTer23	frameshift_variant	24/25	ENST00000322213.9
SMC1A	NM_001281463.1	c.3486_3487insGGCC	p.Ile1163GlyfsTer23	frameshift_variant	25/26

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMC1A	ENST00000322213.9	c.3552_3553insGGCC	p.Ile1185GlyfsTer23	frameshift_variant	24/25	1	NM_006306.4	P1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 22

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy, 85, with or without midline brain defects Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Oct 01, 2015

- -

Congenital muscular hypertrophy-cerebral syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Center for Human Genetics, University Hospitals Case Medical Center/Case Western Reserve University

Sep 08, 2015

Developmental delay and seizures, with either mild or absent classic CdLS facial features. -

Computational scores

Source: dbNSFP v4.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs863225459; hg19: chrX-53407606;