NM_014946.4:c.1245+1G>C

Variant names:

• chr2-32128480-G-C
• rs875989878
• NM_014946.4:c.1245+1G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_014946.4(SPAST):​c.1245+1G>C variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000697 in 1,434,892 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: SPAST NM_014946.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 8.91
• Publications: 7 publications found

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 Gene-Disease associations (from GenCC):

• hereditary spastic paraplegia 4

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Illumina, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), PanelApp Australia, Ambry Genetics, Orphanet
• Charlevoix-Saguenay spastic ataxia

  Inheritance: AR Classification: DEFINITIVE Submitted by: G2P
• neurodevelopmental disorder

  Inheritance: AD Classification: STRONG Submitted by: G2P
• SPAST-related motor disorder

  Inheritance: AR Classification: STRONG Submitted by: Ambry Genetics

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.038897894 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-32128480-G-C is Pathogenic according to our data. Variant chr2-32128480-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 2203040.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_014946.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SPAST	NM_014946.4	MANE Select	c.1245+1G>C		splice_donor intron	N/A	NP_055761.2
	SPAST	NM_001363823.2		c.1242+1G>C		splice_donor intron	N/A	NP_001350752.1	A0A2U3TZR0
	SPAST	NM_199436.2		c.1149+1G>C		splice_donor intron	N/A	NP_955468.1	E5KRP6

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SPAST	ENST00000315285.9	TSL:1 MANE Select	c.1245+1G>C		splice_donor intron	N/A	ENSP00000320885.3	Q9UBP0-1
	SPAST	ENST00000621856.2	TSL:1	c.1242+1G>C		splice_donor intron	N/A	ENSP00000482496.2	A0A2U3TZR0
	SPAST	ENST00000713716.1		c.1350+1G>C		splice_donor intron	N/A	ENSP00000519019.1	A0AAQ5BGQ0

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.97e-7 AC: 1 AN: 1434892 Hom.: 0 Cov.: 25 AF XY: 0.00 AC XY: 0 AN XY: 715442

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 32964

American (AMR) AF: 0.00 AC: 0 AN: 44690

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25952

East Asian (EAS) AF: 0.00 AC: 0 AN: 39500

South Asian (SAS) AF: 0.00 AC: 0 AN: 85724

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53274

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5712

European-Non Finnish (NFE) AF: 9.19e-7 AC: 1 AN: 1087612

Other (OTH) AF: 0.00 AC: 0 AN: 59464

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Hereditary spastic paraplegia 4 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	33
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	1.0	D
PhyloP100		8.9
GERP RS		5.7
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.98		Position offset: -1

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

Other links and lift over

dbSNP: rs875989878; hg19: chr2-32353549;