8-15540383-C-T

Variant names:

• chr8-15540383-C-T
• rs750899051
• NM_006765.4:c.-48C>T

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BS1_Supporting

The NM_006765.4(TUSC3):​c.-48C>T variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000173 in 1,504,958 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000066 (1 hom., cov: 32)
  • Exomes 𝑓: 0.000012 (0 hom.)
• Consequence: TUSC3 NM_006765.4 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.32

Genes affected

TUSC3 (HGNC:30242): (tumor suppressor candidate 3) This gene encodes a protein that has been associated with several biological functions including cellular magnesium uptake, protein glycosylation and embryonic development. This protein localizes to the endoplasmic reticulum and acts as a component of the oligosaccharyl transferase complex which is responsible for N-linked protein glycosylation. This gene is a candidate tumor suppressor gene. Homozygous mutations in this gene are associated with autosomal recessive nonsyndromic mental retardation-7 and in the proliferation and invasiveness of several cancers including metastatic pancreatic cancer, ovarian cancer and glioblastoma multiform. [provided by RefSeq, Oct 2017]

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.28).
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.0000657 (10/152296) while in subpopulation EAS AF= 0.00194 (10/5150). AF 95% confidence interval is 0.00105. There are 1 homozygotes in gnomad4. There are 7 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUSC3	NM_006765.4	c.-48C>T		5_prime_UTR_premature_start_codon_gain_variant	Exon 1 of 11	ENST00000503731.6	NP_006756.2
TUSC3	NM_006765.4	c.-48C>T		5_prime_UTR_variant	Exon 1 of 11	ENST00000503731.6	NP_006756.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TUSC3	ENST00000503731	c.-48C>T		5_prime_UTR_premature_start_codon_gain_variant	Exon 1 of 11	1	NM_006765.4	ENSP00000424544.1
TUSC3	ENST00000503731	c.-48C>T		5_prime_UTR_variant	Exon 1 of 11	1	NM_006765.4	ENSP00000424544.1

Frequencies

GnomAD3 genomes AF: 0.0000657 AC: 10 AN: 152182 Hom.: 1 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00194

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

GnomAD3 exomes AF: 0.0000447 AC: 5 AN: 111910 Hom.: 0 AF XY: 0.0000162 AC XY: 1 AN XY: 61562

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000694

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000118 AC: 16 AN: 1352662 Hom.: 0 Cov.: 31 AF XY: 0.00000903 AC XY: 6 AN XY: 664720

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000409

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.46e-7

Gnomad4 OTH exome AF: 0.0000359

GnomAD4 genome AF: 0.0000657 AC: 10 AN: 152296 Hom.: 1 Cov.: 32 AF XY: 0.0000940 AC XY: 7 AN XY: 74470

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00194

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000529

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital disorder of glycosylation Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

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, 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	-0.28
CADD	Benign	21
DANN	Uncertain	0.97

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs750899051; hg19: chr8-15397892;