2-32136918-C-T

Position:

• chr2-32136918-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Moderate PP5_Moderate

The ENST00000315285.9(SPAST):​c.1363C>T​(p.His455Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H455D) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: SPAST ENST00000315285.9 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.39

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 8 ACMG points.

• PM1: In a hotspot region, there are 10 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in ENST00000315285.9
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.85
• PP5: Variant 2-32136918-C-T is Pathogenic according to our data. Variant chr2-32136918-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 2810687.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SPAST	NM_014946.4	c.1363C>T	p.His455Tyr	missense_variant	11/17	ENST00000315285.9	NP_055761.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SPAST	ENST00000315285.9	c.1363C>T	p.His455Tyr	missense_variant	11/17	1	NM_014946.4	ENSP00000320885	P4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

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

Labcorp Genetics (formerly Invitae), Labcorp

Mar 07, 2023

For these reasons, this variant has been classified as Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SPAST protein function. This missense change has been observed in individual(s) with clinical features of SPAST-related conditions (Invitae). In at least one individual the variant was observed to be de novo. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces histidine, which is basic and polar, with tyrosine, which is neutral and polar, at codon 455 of the SPAST protein (p.His455Tyr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.79
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.21
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.89	D;D;.;.;.;.;.;.
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.97	.;D;D;.;D;D;D;D
M_CAP	Uncertain	0.25	D
MetaRNN	Pathogenic	0.85	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Uncertain	2.6	M;M;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-5.6	D;.;D;.;.;.;.;.
REVEL	Pathogenic	0.76
Sift	Uncertain	0.0010	D;.;D;.;.;.;.;.
Sift4G	Uncertain	0.0020	D;D;D;.;.;.;.;.
Polyphen		1.0	D;D;.;.;.;.;.;.
Vest4		0.77
MutPred		0.59		Gain of phosphorylation at H455 (P = 0.041);Gain of phosphorylation at H455 (P = 0.041);.;.;.;.;.;.;
MVP		0.86
MPC		2.4
ClinPred		0.99	D
GERP RS		5.6
Varity_R		0.94
gMVP		0.94

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

Publications

LitVar

Other links and lift over

dbSNP: rs863224769; hg19: chr2-32361987;