13-37000823-G-T

Variant names:

• chr13-37000823-G-T
• rs1412754843
• NM_181503.3:c.17+1G>T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_181503.3(EXOSC8):​c.17+1G>T variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: EXOSC8 NM_181503.3 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.12

Genes affected

EXOSC8 (HGNC:17035): (exosome component 8) This gene encodes a 3'-5' exoribonuclease that specifically interacts with mRNAs containing AU-rich elements. The encoded protein is part of the exosome complex that is important for the degradation of numerous RNA species. A pseudogene of this gene is found on chromosome 6. [provided by RefSeq, Mar 2009]

ALG5 (HGNC:20266): (ALG5 dolichyl-phosphate beta-glucosyltransferase) This gene encodes a member of the glycosyltransferase 2 family. The encoded protein participates in glucosylation of the oligomannose core in N-linked glycosylation of proteins. The addition of glucose residues to the oligomannose core is necessary to ensure substrate recognition, and therefore, effectual transfer of the oligomannose core to the nascent glycoproteins. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Nov 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
EXOSC8	NM_181503.3	c.17+1G>T		splice_donor_variant, intron_variant	Intron 1 of 10	ENST00000389704.4	NP_852480.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
EXOSC8	ENST00000389704.4	c.17+1G>T		splice_donor_variant, intron_variant	Intron 1 of 10	1	NM_181503.3	ENSP00000374354.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1426678 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 706792

Gnomad4 AFR exome AF: 0.00

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Pontocerebellar hypoplasia, type 1C Uncertain:1

Dec 03, 2018

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: research

The heterozygous c.17+1G>T variant in EXOSC8 was identified by our study in the compound heterozygous state, with a VUS in one individual with pontocerebellar hypoplasia. The c.17+1G>T variant in EXOSC8 has not been previously reported in individuals with pontocerebellar hypoplasia but was absent from large population studies. This variant occurs in the invariant region (+/- 1/2) of the splice consensus sequence and is predicted to cause altered splicing leading to an abnormal or absent protein. However, loss of function of EXOSC8 in an autosomal recessive disease has not yet been established based on the criteria laid out in Tayoun, 2018 (PMID: 30192042). In summary, while there is some suspicion for a pathogenic role, the clinical significance of this variant is uncertain. ACMG/AMP Criteria applied: PM2, PP3 (Richards 2015). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.16
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Uncertain	0.93	D
GERP RS		5.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.95		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.95		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1412754843; hg19: chr13-37574960;