rs1461096954

Positions:

• chr13-23358346-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_014363.6(SACS):​c.593A>G​(p.Tyr198Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,613,870 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: SACS NM_014363.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 8.01

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.933

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SACS	NM_014363.6	c.593A>G	p.Tyr198Cys	missense_variant	7/10	ENST00000382292.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SACS	ENST00000382292.9	c.593A>G	p.Tyr198Cys	missense_variant	7/10	5	NM_014363.6	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152218 Hom.: 0 Cov.: 33

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000410 AC: 6 AN: 1461652 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727146

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: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152218 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74372

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: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Spastic paraplegia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 04, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SACS protein function. ClinVar contains an entry for this variant (Variation ID: 448209). This variant has not been reported in the literature in individuals affected with SACS-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 198 of the SACS protein (p.Tyr198Cys). -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Athena Diagnostics

Sep 26, 2018

- -

Charlevoix-Saguenay spastic ataxia Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Oct 22, 2020

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.48
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.77	D;.;.
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Pathogenic	0.75	D
MetaRNN	Pathogenic	0.93	D;D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	3.5	H;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-5.4	D;.;.
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;.;.
Sift4G	Pathogenic	0.0010	D;.;.
Polyphen		1.0	D;.;.
Vest4		0.98
MutPred		0.72		Gain of catalytic residue at D202 (P = 0);Gain of catalytic residue at D202 (P = 0);Gain of catalytic residue at D202 (P = 0);
MVP		0.97
ClinPred		1.0	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.92
gMVP		0.88

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1461096954; hg19: chr13-23932485; COSMIC: COSV66538129; COSMIC: COSV66538129;