rs796052394

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP3

The NM_000100.4(CSTB):​c.169G>T​(p.Val57Leu) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.00000743 in 1,614,066 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V57M) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000075 ( 0 hom. )

Consequence

CSTB
NM_000100.4 missense, splice_region

Scores

2
9
7
Splicing: ADA: 0.9946
2

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 4.18

Publications

0 publications found
Variant links:
Genes affected
CSTB (HGNC:2482): (cystatin B) The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences. Some of the members are active cysteine protease inhibitors, while others have lost or perhaps never acquired this inhibitory activity. There are three inhibitory families in the superfamily, including the type 1 cystatins (stefins), type 2 cystatins and kininogens. This gene encodes a stefin that functions as an intracellular thiol protease inhibitor. The protein is able to form a dimer stabilized by noncovalent forces, inhibiting papain and cathepsins l, h and b. The protein is thought to play a role in protecting against the proteases leaking from lysosomes. Evidence indicates that mutations in this gene are responsible for the primary defects in patients with progressive myoclonic epilepsy (EPM1). One type of mutation responsible for EPM1 is the expansion in the promoter region of this gene of a CCCCGCCCCGCG repeat from 2-3 copies to 30-78 copies. [provided by RefSeq, Jul 2016]
CSTB Gene-Disease associations (from GenCC):
  • Unverricht-Lundborg syndrome
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, G2P, Orphanet, Labcorp Genetics (formerly Invitae)
  • keratolytic winter erythema
    Inheritance: AD Classification: MODERATE Submitted by: PanelApp Australia
  • genetic developmental and epileptic encephalopathy
    Inheritance: AR Classification: MODERATE Submitted by: ClinGen
  • autosomal recessive hypohidrotic ectodermal dysplasia
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PP3
Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CSTBNM_000100.4 linkc.169G>T p.Val57Leu missense_variant, splice_region_variant Exon 3 of 3 ENST00000291568.7 NP_000091.1 P04080Q76LA1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
CSTBENST00000291568.7 linkc.169G>T p.Val57Leu missense_variant, splice_region_variant Exon 3 of 3 1 NM_000100.4 ENSP00000291568.6 P04080
CSTBENST00000639959.1 linkc.34G>T p.Val12Leu missense_variant, splice_region_variant Exon 2 of 2 5 ENSP00000492123.1 A0A1W2PQG6
CSTBENST00000675996.1 linkn.594G>T splice_region_variant, non_coding_transcript_exon_variant Exon 3 of 3
CSTBENST00000640406.1 linkc.*244G>T 3_prime_UTR_variant Exon 2 of 2 2 ENSP00000492672.1 A0A1W2PS52

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152242
Hom.:
0
Cov.:
33
show subpopulations
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
GnomAD2 exomes
AF:
0.00000398
AC:
1
AN:
251422
AF XY:
0.00
show subpopulations
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000879
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000752
AC:
11
AN:
1461824
Hom.:
0
Cov.:
31
AF XY:
0.00000275
AC XY:
2
AN XY:
727206
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53356
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00000899
AC:
10
AN:
1112010
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60392
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.493
Heterozygous variant carriers
0
1
3
4
6
7
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152242
Hom.:
0
Cov.:
33
AF XY:
0.0000134
AC XY:
1
AN XY:
74376
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41462
American (AMR)
AF:
0.00
AC:
0
AN:
15288
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5200
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4836
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10626
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68038
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.575
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.00000378
EpiCase
AF:
0.00
EpiControl
AF:
0.0000593

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Unverricht-Lundborg syndrome Uncertain:1
Jan 12, 2018
Illumina Laboratory Services, Illumina
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Progressive myoclonic epilepsy Uncertain:1
Jan 02, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 57 of the CSTB protein (p.Val57Leu). This variant is present in population databases (no rsID available, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with CSTB-related conditions. ClinVar contains an entry for this variant (Variation ID: 898861). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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
Uncertain
0.38
BayesDel_addAF
Benign
-0.011
T
BayesDel_noAF
Benign
-0.25
CADD
Uncertain
24
DANN
Uncertain
1.0
DEOGEN2
Benign
0.39
T
Eigen
Pathogenic
0.78
Eigen_PC
Uncertain
0.56
FATHMM_MKL
Uncertain
0.93
D
LIST_S2
Uncertain
0.97
D
M_CAP
Uncertain
0.16
D
MetaRNN
Pathogenic
0.83
D
MetaSVM
Benign
-0.85
T
PhyloP100
4.2
PrimateAI
Uncertain
0.66
T
PROVEAN
Benign
-2.2
N
REVEL
Benign
0.22
Sift
Uncertain
0.0070
D
Sift4G
Uncertain
0.010
D
Polyphen
0.99
D
Vest4
0.58
MutPred
0.67
Loss of methylation at K56 (P = 0.0355);
MVP
0.21
MPC
0.42
ClinPred
0.97
D
GERP RS
4.5
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.91
gMVP
0.51
Mutation Taster
=60/40
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
0.99
dbscSNV1_RF
Pathogenic
0.83
SpliceAI score (max)
0.090
Details are displayed if max score is > 0.2

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

Publications

Other links and lift over

dbSNP: rs796052394; hg19: chr21-45194211; API