Genetic Variant NM_014946.4:c.6_7delTT (chr2-32063836-ATT-A) – ACMG Classification: Pathogenic (12 pts)

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_014946.4(SPAST):c.6_7delTT(p.Pro4GlyfsTer43) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★).

Frequency

Genomes: not found (cov: 32)

Consequence

SPAST
NM_014946.4 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 4.49

Variant links:

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 links:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 94 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 2-32063836-ATT-A is Pathogenic according to our data. Variant chr2-32063836-ATT-A is described in ClinVar as [Pathogenic]. Clinvar id is 468574.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SPAST	NM_014946.4 link	c.6_7delTT	p.Pro4GlyfsTer43	frameshift_variant	Exon 1 of 17	ENST00000315285.9	NP_055761.2	Q9UBP0-1E5KRP5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SPAST	ENST00000315285.9 link	c.6_7delTT	p.Pro4GlyfsTer43	frameshift_variant	Exon 1 of 17	1	NM_014946.4	ENSP00000320885.3		Q9UBP0-1

Frequencies

GnomAD3 genomes

Cov.:

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

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Hereditary spastic paraplegia 4

Pathogenic:1

Nov 27, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Pro4Glyfs*43) in the SPAST gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in SPAST are known to be pathogenic (PMID: 20932283). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SPAST-related conditions. ClinVar contains an entry for this variant (Variation ID: 468574). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing