10-110567702-T-C

Variant summary

Our verdict is Benign. Variant got -7 ACMG points: 0P and 7B. BP4_Moderate BS1_Supporting BS2

The NM_005445.4(SMC3):c.-115T>C variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000145 in 1,312,324 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000053 (0 hom., cov: 34)
  • Exomes 𝑓: 0.0000095 (0 hom.)
• Consequence: SMC3 NM_005445.4 5_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.52

Genes affected

SMC3 (HGNC:2468): (structural maintenance of chromosomes 3) This gene belongs to the SMC3 subfamily of SMC proteins. The encoded protein occurs in certain cell types as either an intracellular, nuclear protein or a secreted protein. The nuclear form, known as structural maintenance of chromosomes 3, is a component of the multimeric cohesin complex that holds together sister chromatids during mitosis, enabling proper chromosome segregation. Post-translational modification of the encoded protein by the addition of chondroitin sulfate chains gives rise to the secreted proteoglycan bamacan, an abundant basement membrane protein. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Benign. Variant got -7 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.29).
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0000525 (8/152252) while in subpopulation AFR AF= 0.000193 (8/41478). AF 95% confidence interval is 0.0000956. There are 0 homozygotes in gnomad4. There are 1 alleles in male gnomad4 subpopulation. Median coverage is 34. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAd at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMC3	NM_005445.4	c.-115T>C		5_prime_UTR_variant	1/29	ENST00000361804.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMC3	ENST00000361804.5	c.-115T>C		5_prime_UTR_variant	1/29	1	NM_005445.4	P1
SMC3	ENST00000684988.1	n.19T>C		non_coding_transcript_exon_variant	1/25
SMC3	ENST00000691297.1	n.19T>C		non_coding_transcript_exon_variant	1/17
SMC3	ENST00000691527.1			upstream_gene_variant

Frequencies

GnomAD3 genomes AF: 0.0000525 AC: 8 AN: 152252 Hom.: 0 Cov.: 34

Gnomad AFR AF: 0.000193

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000948 AC: 11 AN: 1160072 Hom.: 0 Cov.: 15 AF XY: 0.0000102 AC XY: 6 AN XY: 587966

Gnomad4 AFR exome AF: 0.0000365

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000235

Gnomad4 OTH exome AF: 0.000100

GnomAD4 genome AF: 0.0000525 AC: 8 AN: 152252 Hom.: 0 Cov.: 34 AF XY: 0.0000134 AC XY: 1 AN XY: 74386

Gnomad4 AFR AF: 0.000193

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.0000416

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cornelia de Lange syndrome 3 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.29
Cadd	Benign	18
Dann	Benign	0.90
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.2

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: rs886046691; hg19: chr10-112327460;