21-43774324-C-T

Position:

chr21-43774324-C-T

Variant summary

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

The ENST00000291568.7(CSTB):c.175G>A(p.Val59Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000316 in 1,614,176 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts 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. V59V) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000059 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000029 ( 1 hom. )

Consequence

CSTB
ENST00000291568.7 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 2.78

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 links:

Genome browser will be placed here

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=0.14300397).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CSTB	NM_000100.4 linkuse as main transcript	c.175G>A	p.Val59Ile	missense_variant	3/3	ENST00000291568.7	NP_000091.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris
CSTB	ENST00000291568.7 linkuse as main transcript	c.175G>A	p.Val59Ile	missense_variant	3/3	1	NM_000100.4	ENSP00000291568	P1
CSTB	ENST00000639959.1 linkuse as main transcript	c.43G>A	p.Val15Ile	missense_variant	2/2	5		ENSP00000492123
CSTB	ENST00000640406.1 linkuse as main transcript	c.*250G>A		3_prime_UTR_variant	2/2	2		ENSP00000492672
CSTB	ENST00000675996.1 linkuse as main transcript	n.600G>A		non_coding_transcript_exon_variant	3/3

Frequencies

GnomAD3 genomes

AF:

0.0000591

AC:

AN:

152232

Hom.:

Cov.:

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:

0.000413

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000103

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000676

AC:

AN:

251434

Hom.:

AF XY:

0.0000883

AC XY:

AN XY:

135906

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 SAS exome

AF:

0.000392

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000440

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000287

AC:

AN:

1461826

Hom.:

Cov.:

AF XY:

0.0000399

AC XY:

AN XY:

727206

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:

0.000278

Gnomad4 FIN exome

AF:

0.0000375

Gnomad4 NFE exome

AF:

0.0000117

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

AF:

0.0000591

AC:

AN:

152350

Hom.:

Cov.:

AF XY:

0.0000805

AC XY:

AN XY:

74500

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000414

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000103

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000143

Hom.:

Bravo

AF:

0.0000151

ExAC

AF:

0.0000988

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Progressive myoclonic epilepsy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 17, 2023

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 59 of the CSTB protein (p.Val59Ile). This variant is present in population databases (rs531685360, gnomAD 0.04%), including at least one homozygous and/or hemizygous individual. 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: 581672). 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. 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

Benign

0.089

BayesDel_addAF

Benign

-0.35

BayesDel_noAF

Benign

-0.43

CADD

Benign

DANN

Uncertain

1.0

DEOGEN2

Benign

0.17

Eigen

Uncertain

0.19

Eigen_PC

Benign

0.076

FATHMM_MKL

Benign

0.62

LIST_S2

Benign

0.69

M_CAP

Benign

0.021

MetaRNN

Benign

0.14

MetaSVM

Benign

-0.94

MutationTaster

Benign

0.80

PrimateAI

Uncertain

0.56

PROVEAN

Benign

-0.84

REVEL

Benign

0.18

Sift

Benign

0.041

Sift4G

Benign

0.12

Polyphen

1.0

Vest4

0.26

MVP

0.067

MPC

0.28

ClinPred

0.85

GERP RS

5.2

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.64

gMVP

0.21

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

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