rs1553315234

Variant names:

• chr2-32115833-CAAGT-C
• rs1553315234
• NM_014946.4:c.1004+3_1004+6delAAGT

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM2 PP3_Moderate PP5

The NM_014946.4(SPAST):​c.1004+3_1004+6delAAGT variant causes a splice region, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 1/1 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: 32)
• Consequence: SPAST NM_014946.4 splice_region, intron
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 7.89
• Publications: 0 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: Uncertain_significance. The variant received 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 2-32115833-CAAGT-C is Pathogenic according to our data. Variant chr2-32115833-CAAGT-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 448437.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SPAST	NM_014946.4	c.1004+3_1004+6delAAGT		splice_region_variant, intron_variant	Intron 6 of 16	ENST00000315285.9	NP_055761.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SPAST	ENST00000315285.9	c.1003_1004+2delAAGT	p.Asn335GlufsTer9	frameshift_variant, splice_donor_variant, splice_region_variant, intron_variant	Exon 6 of 17	1	NM_014946.4	ENSP00000320885.3

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary spastic paraplegia 4 Pathogenic:1

Jan 06, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 6 of the SPAST gene. It does not directly change the encoded amino acid sequence of the SPAST protein. It affects a nucleotide within the consensus splice site. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individuals with clinical features of SPAST-related disease (internal data). Invitae Evidence Modeling of clinical and family history, age, sex, and reported ancestry of multiple individuals with this SPAST variant has been performed. This variant is expected to be pathogenic with a positive predictive value of at least 99%. This is a validated machine learning model that incorporates the clinical features of 3,690 individuals referred to our laboratory for SPAST testing. ClinVar contains an entry for this variant (Variation ID: 448437). 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. This variant disrupts the c.1004+3A nucleotide in the SPAST gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 28870597). This suggests that this nucleotide is clinically significant, and that variants that disrupt this position are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

not specified Uncertain:1

Jun 13, 2017

Athena Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.9

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: 2

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

Other links and lift over

dbSNP: rs1553315234; hg19: chr2-32340902;