rs138457742

Positions:

• chr13-23354695-T-C

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6 BP7

The NM_014363.6(SACS):​c.1917A>G​(p.Ala639=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000137 in 1,614,062 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 Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00074 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000074 (1 hom.)
• Consequence: SACS NM_014363.6 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:3
• Conservation: PhyloP100: -2.12

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 Likely_benign. Variant got -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.86).
• BP6: Variant 13-23354695-T-C is Benign according to our data. Variant chr13-23354695-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 287300.We mark this variant Likely_benign, oryginal submissions are: {Benign=3, Uncertain_significance=1}.
• BP7: Synonymous conserved (PhyloP=-2.12 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SACS	NM_014363.6	c.1917A>G	p.Ala639=	synonymous_variant	8/10	ENST00000382292.9	NP_055178.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SACS	ENST00000382292.9	c.1917A>G	p.Ala639=	synonymous_variant	8/10	5	NM_014363.6	ENSP00000371729	P1

Frequencies

GnomAD3 genomes AF: 0.000742 AC: 113 AN: 152222 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00265

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

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

GnomAD3 exomes AF: 0.000112 AC: 28 AN: 251096 Hom.: 0 AF XY: 0.0000811 AC XY: 11 AN XY: 135694

Gnomad AFR exome AF: 0.00141

Gnomad AMR exome AF: 0.000145

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000739 AC: 108 AN: 1461722 Hom.: 1 Cov.: 33 AF XY: 0.0000578 AC XY: 42 AN XY: 727148

Gnomad4 AFR exome AF: 0.00269

Gnomad4 AMR exome AF: 0.000157

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: 0.000182

GnomAD4 genome AF: 0.000742 AC: 113 AN: 152340 Hom.: 0 Cov.: 33 AF XY: 0.000671 AC XY: 50 AN XY: 74500

Gnomad4 AFR AF: 0.00264

Gnomad4 AMR AF: 0.000131

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

Alfa AF: 0.000379 Hom.: 0

Bravo AF: 0.000922

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

May 13, 2016

- -

Spastic paraplegia Benign:1

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 31, 2024

- -

not specified Benign:1

Benign, criteria provided, single submitter

clinical testing

Athena Diagnostics

Oct 23, 2019

- -

Charlevoix-Saguenay spastic ataxia Benign:1

Benign, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Sep 05, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.86
CADD	Benign	1.4
DANN	Benign	0.44
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8

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

Other links and lift over

dbSNP: rs138457742; hg19: chr13-23928834;