rs1421791559

chr2-32114825-G-Achr2-32114825-G-Cchr2-32114825-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PP3_Strong PP5_Moderate

The NM_014946.4(SPAST):c.870G>A(p.Lys290=) variant causes a splice region, synonymous change. In-silico tool predicts a benign outcome for this variant. 2/2 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SPAST NM_014946.4 splice_region, synonymous
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.26

Genes affected

SPAST (HGNC:11233): (spastin) This gene encodes a member of the AAA (ATPases associated with a variety of cellular activities) protein family. Members of this protein family share an ATPase domain and have roles in diverse cellular processes including membrane trafficking, intracellular motility, organelle biogenesis, protein folding, and proteolysis. The use of alternative translational initiation sites in this gene results in a single transcript variant that can produce isoforms that differ in the length of their N-terminus and which thereby differ in the efficiency of their export from the nucleus to the cytoplasm. In addition, alternative splicing results in multiple transcript variants that encode isoforms that differ in other protein regions as well. One isoform of this gene has been shown to be a microtubule-severing enzyme that regulates microtubule abundance, mobility, and plus-end distribution. Mutations in this gene cause the most frequent form of autosomal dominant spastic paraplegia 4. [provided by RefSeq, May 2018]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 2-32114825-G-A is Pathogenic according to our data. Variant chr2-32114825-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 468575.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SPAST	NM_014946.4	c.870G>A	p.Lys290=	splice_region_variant, synonymous_variant	5/17	ENST00000315285.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SPAST	ENST00000315285.9	c.870G>A	p.Lys290=	splice_region_variant, synonymous_variant	5/17	1	NM_014946.4	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 1460666 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726772

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary spastic paraplegia 4 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Mar 03, 2020

This sequence change affects codon 290 of the SPAST mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the SPAST protein. This variant also falls at the last nucleotide of exon 5 of the SPAST coding sequence, which is part of the consensus splice site for this exon. This variant is not present in population databases (ExAC no frequency). For these reasons, this variant has been classified as Pathogenic. This variant disrupts the c.870G (also known as 995G) nucleotide in the SPAST gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 11309678). This suggests that this nucleotide is clinically-significant, and that variants that disrupt this position are likely to be disease-causing. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has been observed in individual(s) with hereditary spastic paraplegia (PMID: 18701882, Invitae). ClinVar contains an entry for this variant (Variation ID: 468575). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.28
Cadd	Benign	23
Dann	Benign	0.88

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.90		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.90		Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1421791559; hg19: chr2-32339894;