Genetic Variant CHMP4B:c.483+7A>G (chr20-33851073-A-G) – ACMG Classification: Benign (-10 pts)

Variant summary

Our verdict is Benign. The variant received -10 ACMG points: 0P and 10B. BP4_StrongBP6_ModerateBS2

The NM_176812.5(CHMP4B):c.483+7A>G variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000258 in 1,514,286 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★).

Frequency

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

Exomes 𝑓: 0.000028 ( 0 hom. )

Consequence

CHMP4B
NM_176812.5 splice_region, intron

Scores

Splicing: ADA: 0.00006326

Clinical Significance

Likely benign criteria provided, single submitter B:1

Conservation

PhyloP100: 0.443

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: Benign. The variant received -10 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.89).

BP6

Variant 20-33851073-A-G is Benign according to our data. Variant chr20-33851073-A-G is described in ClinVar as [Likely_benign]. Clinvar id is 3618332.Status of the report is criteria_provided_single_submitter, 1 stars.

BS2

High AC in GnomAdExome4 at 38 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHMP4B	NM_176812.5 link	c.483+7A>G		splice_region_variant, intron_variant	Intron 3 of 4	ENST00000217402.3	NP_789782.1	Q9H444

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHMP4B	ENST00000217402.3 link	c.483+7A>G		splice_region_variant, intron_variant	Intron 3 of 4	1	NM_176812.5	ENSP00000217402.2		Q9H444

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152228

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:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000437

AC:

AN:

251478

AF XY:

0.0000515

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.000893

Gnomad EAS exome

AF:

0.000109

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000279

AC:

AN:

1362058

Hom.:

Cov.:

AF XY:

0.0000337

AC XY:

AN XY:

683388

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

31526

American (AMR)

AF:

0.00

AC:

AN:

44590

Ashkenazi Jewish (ASJ)

AF:

0.00110

AC:

AN:

25488

East Asian (EAS)

AF:

0.0000765

AC:

AN:

39214

South Asian (SAS)

AF:

0.00

AC:

AN:

84170

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53376

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5590

European-Non Finnish (NFE)

AF:

0.00000392

AC:

AN:

1020970

Other (OTH)

AF:

0.0000525

AC:

AN:

57134

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152228

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74378

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

41446

American (AMR)

AF:

0.00

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5204

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68036

Other (OTH)

AF:

0.00

AC:

AN:

2094

⚠️ 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:

0.000189

Hom.:

Bravo

AF:

0.0000227

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Cataract 31 multiple types

Benign:1

Nov 12, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.89

CADD

Benign

(source)

DANN

Benign

0.56

PhyloP100

0.44

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.000063

dbscSNV1_RF

Benign

0.0060

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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chr20-33851073-A-G

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