chr20-33851041-T-C

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2PP2BP4

The NM_176812.5(CHMP4B):c.458T>C(p.Val153Ala) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,610,858 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

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

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

CHMP4B
NM_176812.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 6.27

Publications

0 publications found

Variant links:

Genes affected

CHMP4B (HGNC:16171): (charged multivesicular body protein 4B) This gene encodes a member of the chromatin-modifying protein/charged multivesicular body protein (CHMP) protein family. The protein is part of the endosomal sorting complex required for transport (ESCRT) complex III (ESCRT-III), which functions in the sorting of endocytosed cell-surface receptors into multivesicular endosomes. The ESCRT machinery also functions in the final abscisson stage of cytokinesis and in the budding of enveloped viruses such as HIV-1. The three proteins of the CHMP4 subfamily interact with programmed cell death 6 interacting protein (PDCD6IP, also known as ALIX), which also functions in the ESCRT pathway. The CHMP4 proteins assemble into membrane-attached 5-nm filaments that form circular scaffolds and promote or stabilize outward budding. These polymers are proposed to help generate the luminal vesicles of multivesicular bodies. Mutations in this gene result in autosomal dominant posterior polar cataracts.[provided by RefSeq, Oct 2009]

CHMP4B Gene-Disease associations (from GenCC):

cataract 31 multiple types
Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
early-onset posterior polar cataract
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
early-onset posterior subcapsular cataract
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

CHMP4B links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 3 curated pathogenic missense variants (we use a threshold of 10). The gene has 0 curated benign missense variants. Gene score misZ: 2.3781 (below the threshold of 3.09). Trascript score misZ: 2.8898 (below the threshold of 3.09). GenCC associations: The gene is linked to early-onset posterior subcapsular cataract, cataract 31 multiple types, early-onset posterior polar cataract.

BP4

Computational evidence support a benign effect (MetaRNN=0.4090055).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHMP4B	NM_176812.5 link	c.458T>C	p.Val153Ala	missense_variant	Exon 3 of 5	ENST00000217402.3	NP_789782.1	Q9H444

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHMP4B	ENST00000217402.3 link	c.458T>C	p.Val153Ala	missense_variant	Exon 3 of 5	1	NM_176812.5	ENSP00000217402.2		Q9H444

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152164

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1458694

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

725836

show subpopulations

African (AFR)

AF:

0.0000599

AC:

AN:

33410

American (AMR)

AF:

0.00

AC:

AN:

44718

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26106

East Asian (EAS)

AF:

0.00

AC:

AN:

39686

South Asian (SAS)

AF:

0.00

AC:

AN:

86188

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1109138

Other (OTH)

AF:

0.00

AC:

AN:

60268

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152164

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74342

show subpopulations

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

African (AFR)

AF:

0.0000241

AC:

AN:

41452

American (AMR)

AF:

0.00

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2090

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Feb 13, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.458T>C (p.V153A) alteration is located in exon 3 (coding exon 3) of the CHMP4B gene. This alteration results from a T to C substitution at nucleotide position 458, causing the valine (V) at amino acid position 153 to be replaced by an alanine (A). 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

Uncertain

0.35

BayesDel_addAF

Uncertain

0.15

BayesDel_noAF

Uncertain

-0.020

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.66

Eigen

Benign

0.18

Eigen_PC

Uncertain

0.36

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.85

M_CAP

Benign

0.020

MetaRNN

Benign

0.41

MetaSVM

Benign

-0.60

MutationAssessor

Benign

1.7

PhyloP100

6.3

PrimateAI

Pathogenic

0.88

PROVEAN

Uncertain

-2.6

REVEL

Uncertain

0.44

Sift

Benign

0.042

Sift4G

Benign

0.11

Polyphen

0.087

Vest4

0.50

MutPred

0.64

Gain of catalytic residue at V153 (P = 0.06);

MVP

0.79

MPC

1.4

ClinPred

0.91

GERP RS

6.0

Varity_R

0.38

gMVP

0.73

Mutation Taster

=43/57

disease causing

(source)

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

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chr20-33851041-T-C

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over