2-32136933-C-T

Position:

• chr2-32136933-C-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_014946.4(SPAST):​c.1378C>T​(p.Arg460Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,316 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging 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. R460S) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: SPAST NM_014946.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:14
• Conservation: PhyloP100: 3.42

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 Pathogenic. Variant got 16 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-32136933-C-A is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989
• PP5: Variant 2-32136933-C-T is Pathogenic according to our data. Variant chr2-32136933-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 240948.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-32136933-C-T is described in UniProt as null. Variant chr2-32136933-C-T is described in Lovd as [Pathogenic]. Variant chr2-32136933-C-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SPAST	NM_014946.4	c.1378C>T	p.Arg460Cys	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.1378C>T	p.Arg460Cys	missense_variant	11/17	1	NM_014946.4	ENSP00000320885.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461316 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 727006

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: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:14

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:7

Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Aug 29, 2018	Not found in the total gnomAD dataset, and the data is high quality (0/276546 chr). Statistically enriched in patients compared to ethnically matched controls. Predicted to have a damaging effect on the protein. Located in potentially critical domain of the protein. Two other pathogenic or likely pathogenic variants affect the same amino acid. Co-occurs with otherwise positive results less than expected. -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen	Oct 23, 2020	- -
Pathogenic, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Mar 01, 2020	- -
Likely pathogenic, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Jun 21, 2023	PP2, PP3, PM1, PM2, PS4 -
Pathogenic, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -

Hereditary spastic paraplegia 4 Pathogenic:6

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 21, 2023	This missense change has been observed in individuals with hereditary spastic paraplegia (PMID: 15248095, 15482961, 16055926, 16832076, 17594340, 18701882, 20718791, 22960362, 24451228, 25658484). ClinVar contains an entry for this variant (Variation ID: 240948). 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 is located in a region of the SPAST protein in which a significant number of missense variants have been reported (PMID: 11809724). These observations suggest that this may be a clinically significant region of the protein. For these reasons, this variant has been classified as Pathogenic. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 460 of the SPAST protein (p.Arg460Cys). -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 09, 2023	Variant summary: SPAST c.1378C>T (p.Arg460Cys) results in a non-conservative amino acid change located in the AAA+ ATPase domain (IPR003593) of the encoded protein sequence. This alters a well-conserved residue in which several missense changes have been found in association with Spastic paraplegia (HGMD), two of which (p.Arg460Leu, p.Arg460His) have been classified as pathogenic or likely pathogenic by ClinVar submitters. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251056 control chromosomes (gnomAD). c.1378C>T has been reported in the literature in multiple individuals affected with Spastic Paraplegia 4, Autosomal Dominant (e.g. Falco_2004, Burguez_2017, Mereaux_2022). These data indicate that the variant is very likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 15482961, 29246610, 34983064). Eight submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Oct 19, 2020	Based on the classification scheme VCGS_Germline_v1.3.3, this variant is classified as Pathogenic. Following criteria are met: 0103 - Loss of function and dominant negative are known mechanisms of disease for this gene and are associated with autosomal dominant spastic paraplegia 4 (MIM#182601). Multiple loss of function variants have been reported, while a dominant negative mechanism has been stipulated for a small number of missense variants (ClinVar; PMID: 30006150). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0112 - The condition associated with this gene has incomplete penetrance. The penetrance is mostly complete and is lower in females (PMID: 30476002). (I) 0115 - Variants in this gene are known to have variable expressivity. Age at onset of symptoms ranges from infancy to the eighth decade and there is significant intrafamilial clinical variability (PMID: 30476002). (I) 0200 - Variant is predicted to result in a missense amino acid change from arginine to cysteine. (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0603 - Missense variant in a region that is highly intolerant to missense variation (high constraint region in DECIPHER). It is also located in the annotated AAA domain (PDB), where most missense variants reported are located (PMID: 30476002). (SP) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. It has been reported in many unrelated families with hereditary spastic paraplegia (ClinVar, PMIDs: 30778698, 29246610, 27688599, 28572275). (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
Pathogenic, criteria provided, single submitter	clinical testing	Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein	Feb 03, 2023	ACMG classification criteria: PS4 strong, PM1 moderated, PM2 moderated, PP1 strong, PP3 supporting -
Pathogenic, criteria provided, single submitter	clinical testing	Paris Brain Institute, Inserm - ICM	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	MGZ Medical Genetics Center	May 23, 2022	- -

Hereditary spastic paraplegia Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Genome Diagnostics Laboratory, The Hospital for Sick Children

May 01, 2020

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.48
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.97	D;D;.;.;.;.;.;.
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.96	.;D;D;.;D;D;D;D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.1	M;M;.;.;.;.;.;.
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-8.0	D;.;D;.;.;.;.;.
REVEL	Pathogenic	0.88
Sift	Pathogenic	0.0	D;.;D;.;.;.;.;.
Sift4G	Pathogenic	0.0	D;D;D;.;.;.;.;.
Polyphen		1.0	D;D;.;.;.;.;.;.
Vest4		0.95
MutPred		0.96		Gain of catalytic residue at L461 (P = 0.0116);Gain of catalytic residue at L461 (P = 0.0116);.;.;.;.;.;.;
MVP		0.98
MPC		1.6
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.96
gMVP		0.93

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: rs878854990; hg19: chr2-32362002; COSMIC: COSV59518285;