rs771943685

Variant names:

• chr13-23411239-T-C
• rs771943685
• NM_014363.6:c.1A>G
• SACS p.Met1?

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_014363.6(SACS):​c.1A>G​(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000055 in 1,454,952 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: not found (cov: 33)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: SACS NM_014363.6 start_lost
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 3.53
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• Charlevoix-Saguenay spastic ataxia

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Myriad Women's Health, Orphanet, G2P, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, PanelApp Australia

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Start lost variant, next in-frame start position is after 35 pathogenic variants. Next in-frame start position is after 148 codons. Genomic position: 23365181. Lost 0.032 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-23411239-T-C is Pathogenic according to our data. Variant chr13-23411239-T-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 370666.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_014363.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SACS	NM_014363.6	MANE Select	c.1A>G	p.Met1?	start_lost	Exon 2 of 10	NP_055178.3
	SACS	NM_001437336.1		c.1A>G	p.Met1?	start_lost	Exon 2 of 11	NP_001424265.1	A0A804HIQ1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SACS	ENST00000382292.9	TSL:5 MANE Select	c.1A>G	p.Met1?	start_lost	Exon 2 of 10	ENSP00000371729.3	Q9NZJ4-1
	SACS	ENST00000455470.6	TSL:1	c.1A>G	p.Met1?	start_lost	Exon 2 of 11	ENSP00000406565.2	H0Y6M8
	SACS	ENST00000682944.1		c.1A>G	p.Met1?	start_lost	Exon 2 of 11	ENSP00000507173.1	A0A804HIQ1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.0000161 AC: 4 AN: 248672 AF XY: 0.0000296

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000550 AC: 8 AN: 1454952 Hom.: 0 Cov.: 28 AF XY: 0.00000966 AC XY: 7 AN XY: 724266

African (AFR) AF: 0.00 AC: 0 AN: 33370

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26072

East Asian (EAS) AF: 0.00 AC: 0 AN: 39638

South Asian (SAS) AF: 0.0000930 AC: 8 AN: 86066

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53382

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1105816

Other (OTH) AF: 0.00 AC: 0 AN: 60126

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
2	-	-	Charlevoix-Saguenay spastic ataxia (2)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Uncertain	0.013	T
BayesDel_noAF	Uncertain	0.020
CADD	Benign	20
DANN	Uncertain	0.98
DEOGEN2	Benign	0.14	T
Eigen	Benign	-0.014
Eigen_PC	Benign	0.14
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Uncertain	-0.24	T
PhyloP100		3.5
PROVEAN	Benign	-0.27	N
REVEL	Uncertain	0.49
Sift	Pathogenic	0.0	D
Varity_R		0.85
gMVP		0.58
Mutation Taster		=9/191	disease causing (ClinVar)

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs771943685;

hg19: chr13-23985378;