rs780247476

Positions:

chr13-23332970-G-A

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_014363.6(SACS):c.10906C>T(p.Arg3636Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000167 in 1,613,678 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000017 ( 0 hom. )

Consequence

SACS
NM_014363.6 stop_gained

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8

Conservation

PhyloP100: 2.72

Variant links:

Genes affected

SACS (HGNC:10519): (sacsin molecular chaperone) This gene encodes the sacsin protein, which includes a UbL domain at the N-terminus, a DnaJ domain, and a HEPN domain at the C-terminus. The gene is highly expressed in the central nervous system, also found in skin, skeletal muscles and at low levels in the pancreas. This gene includes a very large exon spanning more than 12.8 kb. Mutations in this gene result in autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), a neurodegenerative disorder characterized by early-onset cerebellar ataxia with spasticity and peripheral neuropathy. The authors of a publication on the effects of siRNA-mediated sacsin knockdown concluded that sacsin protects against mutant ataxin-1 and suggest that "the large multi-domain sacsin protein is able to recruit Hsp70 chaperone action and has the potential to regulate the effects of other ataxia proteins" (Parfitt et al., PubMed: 19208651). A pseudogene associated with this gene is located on chromosome 11. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, May 2013]

SACS links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 45 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 13-23332970-G-A is Pathogenic according to our data. Variant chr13-23332970-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 212108.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr13-23332970-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SACS	NM_014363.6 linkuse as main transcript	c.10906C>T	p.Arg3636Ter	stop_gained	10/10	ENST00000382292.9	NP_055178.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SACS	ENST00000382292.9 linkuse as main transcript	c.10906C>T	p.Arg3636Ter	stop_gained	10/10	5	NM_014363.6	ENSP00000371729	P1	Q9NZJ4-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000120

AC:

AN:

250508

Hom.:

AF XY:

0.00000738

AC XY:

AN XY:

135480

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000177

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.0000171

AC:

AN:

1461506

Hom.:

Cov.:

AF XY:

0.0000124

AC XY:

AN XY:

727052

show subpopulations

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:

0.0000216

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74334

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.0000294

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000756

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Charlevoix-Saguenay spastic ataxia

Pathogenic:6

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Feb 14, 2020	Variant summary: SACS c.10906C>T (p.Arg3636X) results in a premature termination codon in the last exon, that is not expected to result in nonsense mediated decay (NMD), but is predicted to cause a large truncation of the encoded protein. Truncations downstream of this position have been classified as pathogenic by our laboratory (e.g. c.11374C>T (p.Arg3792X)). The variant allele was found at a frequency of 1.2e-05 in 250508 control chromosomes (gnomAD). The variant, c.10906C>T, has been reported in the literature in multiple compound heterozygous- and a homozygous individual affected with Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (Vermeer_2008, Walsh_2017, Sun_2019, Tsugawa_2015). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and laboratories classified the variant as pathogenic (1x) / likely pathogenic (1x). Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Aug 07, 2014	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Sep 05, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Feb 19, 2016	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Jul 14, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Dec 11, 2023	- -

Spastic paraplegia

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 01, 2024

This sequence change creates a premature translational stop signal (p.Arg3636*) in the SACS gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 944 amino acid(s) of the SACS protein. This variant is present in population databases (rs780247476, gnomAD 0.002%). This premature translational stop signal has been observed in individual(s) with early-onset cerebellar ataxia (PMID: 18465152). ClinVar contains an entry for this variant (Variation ID: 212108). This variant disrupts a region of the SACS protein in which other variant(s) (p.Arg3903*) have been determined to be pathogenic (PMID: 19892370, 21745802). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Inborn genetic diseases

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 03, 2020

The c.10906C>T (p.R3636*) alteration, located in exon 10 (coding exon 9) of the SACS gene, consists of a C to T substitution at nucleotide position 10906. This changes the amino acid from an arginine (R) to a stop codon at amino acid position 3636. This alteration occurs at the 3' terminus of the SACS gene, is not expected to trigger nonsense-mediated mRNA decay, and only impacts the last 20% of the protein. However, premature stop codons are typically deleterious in nature and a pathogenic truncating mutation downstream has been reported (Vermeer, 2008). This alteration was reported in two brothers and another unrelated patient with autosomal recessive spastic ataxia of Charlevoix Saguenay. They were all found to be compound heterozygous for a second truncating alteration in SACS (Vermeer, 2008; Sun, 2019). Based on the available evidence, this alteration is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.61

BayesDel_noAF

Pathogenic

0.51

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Uncertain

0.66

Eigen_PC

Uncertain

0.53

FATHMM_MKL

Uncertain

0.85

MutationTaster

Benign

1.0

D;D;D

Vest4

0.94

GERP RS

4.3

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over