Genetic Variant SPG21:p.Ala291Thr (chr15-64963676-C-T) – ACMG Classification: Uncertain_significance (0 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_016630.7(SPG21):c.871G>A(p.Ala291Thr) variant causes a missense change. The variant allele was found at a frequency of 0.0000186 in 1,614,048 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. A291A) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000019 ( 0 hom. )

Consequence

SPG21
NM_016630.7 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 4.59

Variant links:

Genes affected

SPG21 (HGNC:20373): (SPG21 abhydrolase domain containing, maspardin) The protein encoded by this gene binds to the hydrophobic C-terminal amino acids of CD4 which are involved in repression of T cell activation. The interaction with CD4 is mediated by the noncatalytic alpha/beta hydrolase fold domain of this protein. It is thus proposed that this gene product modulates the stimulatory activity of CD4. Mutations in this gene are associated with autosomal recessive spastic paraplegia 21 (SPG21), also known as mast syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2014]

SPG21 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.14509273).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
SPG21	NM_016630.7 link	c.871G>A	p.Ala291Thr	missense_variant	Exon 9 of 9	ENST00000204566.7	NP_057714.1
SPG21	NM_001127889.5 link	c.871G>A	p.Ala291Thr	missense_variant	Exon 9 of 9		NP_001121361.1
SPG21	NM_001127890.5 link	c.790G>A	p.Ala264Thr	missense_variant	Exon 8 of 8		NP_001121362.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SPG21	ENST00000204566.7 link	c.871G>A	p.Ala291Thr	missense_variant	Exon 9 of 9	1	NM_016630.7	ENSP00000204566.2		Q9NZD8-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152216

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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

AF:

0.0000192

AC:

AN:

1461832

Hom.:

Cov.:

AF XY:

0.0000151

AC XY:

AN XY:

727228

show subpopulations

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:

0.0000252

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152216

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74370

show subpopulations

Gnomad4 AFR

AF:

0.0000241

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

Bravo

AF:

0.0000113

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Sep 28, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.871G>A (p.A291T) alteration is located in exon 9 (coding exon 8) of the SPG21 gene. This alteration results from a G to A substitution at nucleotide position 871, causing the alanine (A) at amino acid position 291 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.068

BayesDel_addAF

Benign

-0.046

BayesDel_noAF

Benign

-0.30

CADD

Benign

DANN

Uncertain

1.0

DEOGEN2

Benign

0.13

T;.;T;.

Eigen

Benign

-0.045

Eigen_PC

Benign

0.18

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Uncertain

0.93

.;D;D;D

M_CAP

Benign

0.0036

MetaRNN

Benign

0.15

T;T;T;T

MetaSVM

Benign

-0.99

MutationAssessor

Benign

0.55

N;.;N;.

PrimateAI

Uncertain

0.69

PROVEAN

Benign

-0.17

N;N;N;N

REVEL

Benign

0.27

Sift

Benign

0.079

T;T;T;T

Sift4G

Benign

0.36

T;T;T;T

Polyphen

0.047

B;.;B;B

Vest4

0.20

MutPred

0.22

Gain of glycosylation at A291 (P = 0.018);.;Gain of glycosylation at A291 (P = 0.018);.;

MVP

0.28

MPC

0.33

ClinPred

0.50

GERP RS

5.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.080

gMVP

0.72

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.060

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over