rs587777754

Variant names:

• chr2-32147259-G-A
• rs587777754
• NM_014946.4:c.1728+1G>A

Your query was ambiguous. Multiple possible variants found:

• chr2-32147259-G-A
• chr2-32147259-G-C
• chr2-32147259-G-T

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The NM_014946.4(SPAST):​c.1728+1G>A variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 31)
• Consequence: SPAST NM_014946.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 6.85
• Publications: 3 publications found

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]

SPAST Gene-Disease associations (from GenCC):

• hereditary spastic paraplegia 4

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Illumina, Genomics England PanelApp, Ambry Genetics
• Charlevoix-Saguenay spastic ataxia

  Inheritance: AR Classification: DEFINITIVE Submitted by: G2P
• neurodevelopmental disorder

  Inheritance: AD Classification: STRONG Submitted by: G2P
• SPAST-related motor disorder

  Inheritance: AR Classification: STRONG Submitted by: Ambry Genetics

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3.7, offset of -5, new splice context is: ccaGTgaga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-32147259-G-A is Pathogenic according to our data. Variant chr2-32147259-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 566838.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SPAST	NM_014946.4	c.1728+1G>A		splice_donor_variant, intron_variant	Intron 16 of 16	ENST00000315285.9	NP_055761.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SPAST	ENST00000315285.9	c.1728+1G>A		splice_donor_variant, intron_variant	Intron 16 of 16	1	NM_014946.4	ENSP00000320885.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Oct 18, 2024

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not expected to cause loss of protein expression through nonsense-mediated decay. However, similar variants in this region have been associated with disease, and therefore, this variant is also expected to associate with disease. This variant has been identified in multiple unrelated individuals with clinical features associated with this gene. In some published literature, this variant is referred to as c.1853+1G>A. -

Sep 26, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 31227335, 25525159, 29980238, 21546041, 31751864, 10699187, 15841487, 36825575, 30564185) -

Hereditary spastic paraplegia 4 Pathogenic:2

-

Paris Brain Institute, Inserm - ICM

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 20, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. Variants that disrupt 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. ClinVar contains an entry for this variant (Variation ID: 566838). This variant is also known as c.1853+1G>A. Disruption of this splice site has been observed in individuals with autosomal dominant herditary spastic paraplegia (PMID: 10699187, 15841487). This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 16 of the SPAST gene. While this variant is not anticipated to result in nonsense mediated decay, it likely alters RNA splicing and results in a disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		6.9
GERP RS		5.6
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.98		Position offset: -1

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

Other links and lift over

dbSNP: rs587777754; hg19: chr2-32372328;