chrX-53411822-C-T

Position:

• chrX-53411822-C-T

Variant summary

Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. PM2 PM5 PP2 PP3_Moderate PP5_Very_Strong

The NM_006306.4(SMC1A):​c.1193G>A​(p.Arg398Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R398G) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 22)
• Consequence: SMC1A NM_006306.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.52

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 15 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SMC1A. . Gene score misZ 6.4479 (greater than the threshold 3.09). GenCC has associacion of gene with 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.904
• PP5: Variant X-53411822-C-T is Pathogenic according to our data. Variant chrX-53411822-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 159938.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chrX-53411822-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SMC1A	NM_006306.4	c.1193G>A	p.Arg398Gln	missense_variant	7/25	ENST00000322213.9	NP_006297.2
SMC1A	NM_001281463.1	c.1127G>A	p.Arg376Gln	missense_variant	8/26		NP_001268392.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SMC1A	ENST00000322213.9	c.1193G>A	p.Arg398Gln	missense_variant	7/25	1	NM_006306.4	ENSP00000323421.3

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 22

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital muscular hypertrophy-cerebral syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 01, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Feb 08, 2013	- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jul 25, 2024

Not observed at significant frequency in large population cohorts (gnomAD); Missense variants in this gene are a common cause of disease and they are underrepresented in the general population; In silico analysis indicates that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 22140011, 19842212, 28548707, 26358754, 24124034, 19701948) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.30
CADD	Uncertain	23
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.41	T;T
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.90	D;D
MetaSVM	Uncertain	0.33	D
MutationAssessor	Benign	2.0	M;.
PrimateAI	Pathogenic	0.79	T
PROVEAN	Benign	-2.3	N;.
REVEL	Pathogenic	0.76
Sift	Benign	0.27	T;.
Sift4G	Benign	0.36	T;T
Polyphen		0.98	D;.
Vest4		0.60
MutPred		0.82		Loss of MoRF binding (P = 0.0471);.;
MVP		0.98
MPC		3.0
ClinPred		0.96	D
GERP RS		4.8
RBP_binding_hub_radar		1.0
RBP_regulation_power_radar		2.2
Varity_R		0.59
gMVP		0.75

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: rs587784403; hg19: chrX-53438772; COSMIC: COSV100447086; COSMIC: COSV100447086;