13-23335082-GTTTT-GTTT

Variant names:

Variant summary

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

The NM_014363.6(SACS):c.8793delA(p.Lys2931AsnfsTer22) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,613,304 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

SACS
NM_014363.6 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:9

Conservation

PhyloP100: -0.798

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 55 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 13-23335082-GT-G is Pathogenic according to our data. Variant chr13-23335082-GT-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 449517.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SACS	NM_014363.6 link	c.8793delA	p.Lys2931AsnfsTer22	frameshift_variant	Exon 10 of 10	ENST00000382292.9	NP_055178.3	Q9NZJ4-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SACS	ENST00000382292.9 link	c.8793delA	p.Lys2931AsnfsTer22	frameshift_variant	Exon 10 of 10	5	NM_014363.6	ENSP00000371729.3		Q9NZJ4-1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152022

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:

0.000192

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:

0.00000399

AC:

AN:

250652

Hom.:

AF XY:

0.00000738

AC XY:

AN XY:

135498

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:

0.0000328

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461282

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726892

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:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

9.00e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152022

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74272

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000192

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:9

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Charlevoix-Saguenay spastic ataxia

Pathogenic:6

Mar 22, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 29, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 04, 2018

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sep 05, 2021

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 06, 2018

Institute of Human Genetics Munich, Klinikum Rechts Der Isar, TU München

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 11, 2021

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: SACS c.8793delA (p.Lys2931AsnfsX22) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 4e-06 in 250652 control chromosomes. c.8793delA has been reported in the literature as a homozygous mutation in several individuals affected with Autosomal Recessive Spastic Ataxia Of Charlevoix-Saguenay, including 2 affected siblings (e.g. Hara_2005, Shakya_2019). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories cited the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided

Pathogenic:2

Aug 17, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation, as the last 1649 amino acids are replaced with 21 different amino acids, and other loss-of-function variants have been reported downstream in HGMD.; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 15486997, 31429931, 32606540, Sheetal_2021_article, 35499206) -

Jun 22, 2023

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The frequency of this variant in the general population is consistent with pathogenicity (http://gnomad.broadinstitute.org). This variant is not expected to cause loss of protein expression through nonsense-mediated decay, however, it disrupts an critical region of the protein, and therefore, is expected to severely disrupt function. This variant has been identified in at least one individual with clinical features associated with this gene. -

Spastic paraplegia

Pathogenic:1

Jan 17, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Lys2931Asnfs*22) in the SACS gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 1649 amino acid(s) of the SACS protein. This variant is present in population databases (no rsID available, gnomAD 0.003%). This premature translational stop signal has been observed in individual(s) with autosomal recessive spastic ataxia (PMID: 15486997). It has also been observed to segregate with disease in related individuals. This variant is also known as 6543delA. ClinVar contains an entry for this variant (Variation ID: 449517). This variant disrupts a region of the SACS protein in which other variant(s) (p.Arg3636*) have been determined to be pathogenic (PMID: 18465152). 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

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