rs1553316838

Positions:

• chr2-32127013-G-C
• chr2-32127013-G-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_014946.4(SPAST):​c.1164G>C​(p.Lys388Asn) variant causes a missense change involving the alteration of a non-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. K388R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: SPAST NM_014946.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 0.235

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 Pathogenic. Variant got 12 ACMG points.

• PM1: In a binding_site (size 7) in uniprot entity SPAST_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_014946.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.98
• PP5: Variant 2-32127013-G-C is Pathogenic according to our data. Variant chr2-32127013-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 1454039.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.1164G>C	p.Lys388Asn	missense_variant	8/17	ENST00000315285.9	NP_055761.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SPAST	ENST00000315285.9	c.1164G>C	p.Lys388Asn	missense_variant	8/17	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: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

Nov 28, 2022

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. ClinVar contains an entry for this variant (Variation ID: 1454039). This missense change has been observed in individual(s) with clinical features of hereditary spastic paraplegia (PMID: 30476002). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces lysine, which is basic and polar, with asparagine, which is neutral and polar, at codon 388 of the SPAST protein (p.Lys388Asn). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.29
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D;D;.;.;.;.;.;.
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.31
FATHMM_MKL	Uncertain	0.80	D
LIST_S2	Uncertain	0.90	.;D;D;.;D;D;D;D
M_CAP	Pathogenic	0.76	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.7	H;H;.;.;.;.;.;.
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-4.8	D;.;D;.;.;.;.;.
REVEL	Pathogenic	0.84
Sift	Uncertain	0.0010	D;.;D;.;.;.;.;.
Sift4G	Uncertain	0.0030	D;D;D;.;.;.;.;.
Polyphen		1.0	D;D;.;.;.;.;.;.
Vest4		0.96
MutPred		0.92		Loss of methylation at K388 (P = 0.0057);Loss of methylation at K388 (P = 0.0057);.;.;.;.;.;.;
MVP		0.97
MPC		2.4
ClinPred		1.0	D
GERP RS		-0.42
Varity_R		0.99
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr2-32352082;