NM_014946.4:c.1121C>T

Variant names:

• chr2-32126970-C-T
• rs1471030618
• NM_014946.4:c.1121C>T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Moderate PP5_Moderate

The NM_014946.4(SPAST):​c.1121C>T​(p.Pro374Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,114 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 31)
• Consequence: SPAST NM_014946.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.32

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 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.904
• PP5: Variant 2-32126970-C-T is Pathogenic according to our data. Variant chr2-32126970-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 536437.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	c.1121C>T	p.Pro374Leu	missense_variant	Exon 8 of 17	ENST00000315285.9	NP_055761.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SPAST	ENST00000315285.9	c.1121C>T	p.Pro374Leu	missense_variant	Exon 8 of 17	1	NM_014946.4	ENSP00000320885.3

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152114 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 28

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152114 Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1 AN XY: 74294

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary spastic paraplegia 4 Pathogenic:1

Feb 10, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 374 of the SPAST protein (p.Pro374Leu). This variant is present in population databases (no rsID available, gnomAD 0.007%). This missense change has been observed in individuals with hereditary spastic paraplegia (Invitae). ClinVar contains an entry for this variant (Variation ID: 536437). 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 variant disrupts the p.Pro374 amino acid residue in SPAST. Other variant(s) that disrupt this residue have been observed in individuals with SPAST-related conditions (PMID: 16009377, 18701882), which suggests that this may be a clinically significant amino acid residue. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.21
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.77	D;D;.;.;.;.;.;.
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	.;D;D;.;D;D;D;D
M_CAP	Uncertain	0.27	D
MetaRNN	Pathogenic	0.90	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.1	M;M;.;.;.;.;.;.
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-9.7	D;.;D;.;.;.;.;.
REVEL	Pathogenic	0.75
Sift	Benign	0.069	T;.;T;.;.;.;.;.
Sift4G	Pathogenic	0.0	D;D;D;.;.;.;.;.
Polyphen		1.0	D;D;.;.;.;.;.;.
Vest4		0.83
MutPred		0.72		Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);.;.;.;.;.;.;
MVP		0.71
MPC		2.3
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.90
gMVP		0.95

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.10		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: rs1471030618; hg19: chr2-32352039; COSMIC: COSV59517268;