rs746073001

Positions:

• chr2-32089530-T-C

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4 BS2

The NM_014946.4(SPAST):​c.511T>C​(p.Cys171Arg) variant causes a missense change. The variant allele was found at a frequency of 0.0000063 in 1,428,132 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000063 (0 hom.)
• Consequence: SPAST NM_014946.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.69

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 (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.27010772).
• BS2: High AC in GnomAdExome4 at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SPAST	NM_014946.4	c.511T>C	p.Cys171Arg	missense_variant	3/17	ENST00000315285.9	NP_055761.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SPAST	ENST00000315285.9	c.511T>C	p.Cys171Arg	missense_variant	3/17	1	NM_014946.4	ENSP00000320885.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251328 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135830

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000630 AC: 9 AN: 1428132 Hom.: 0 Cov.: 26 AF XY: 0.00000561 AC XY: 4 AN XY: 712688

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000832

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary spastic paraplegia 4 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 23, 2023

This sequence change replaces cysteine, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 171 of the SPAST protein (p.Cys171Arg). This variant is present in population databases (rs746073001, gnomAD 0.0009%). 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: 536452). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on SPAST protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Uncertain	0.017	T
BayesDel_noAF	Benign	-0.21
CADD	Benign	21
DANN	Benign	0.96
DEOGEN2	Benign	0.27	T;T;.;.;.;.;.;.
Eigen	Benign	0.0066
Eigen_PC	Benign	0.16
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.86	.;D;D;.;D;D;T;T
M_CAP	Benign	0.025	T
MetaRNN	Benign	0.27	T;T;T;T;T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.90	L;L;L;L;.;.;.;.
PrimateAI	Uncertain	0.74	T
PROVEAN	Uncertain	-2.4	N;.;N;.;.;.;.;.
REVEL	Benign	0.27
Sift	Benign	0.089	T;.;T;.;.;.;.;.
Sift4G	Benign	0.29	T;T;T;.;.;.;.;.
Polyphen		0.0080	B;B;.;.;.;.;.;.
Vest4		0.59
MVP		0.30
MPC		0.34
ClinPred		0.54	D
GERP RS		4.6
Varity_R		0.49
gMVP		0.52

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: rs746073001; hg19: chr2-32314599;