rs118203965

Variant names:

• chr20-33850969-A-T
• rs118203965
• NM_176812.5:c.386A>T

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM2 PP2 PP3_Strong PP5

The NM_176812.5(CHMP4B):​c.386A>T​(p.Asp129Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: CHMP4B NM_176812.5 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 9.25
• Publications: 13 publications found

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

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.98
• PP5: Variant 20-33850969-A-T is Pathogenic according to our data. Variant chr20-33850969-A-T is described in ClinVar as Pathogenic. ClinVar VariationId is 1085.Status of the report is no_assertion_criteria_provided, 0 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_176812.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHMP4B	NM_176812.5	MANE Select	c.386A>T	p.Asp129Val	missense	Exon 3 of 5	NP_789782.1	Q9H444

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHMP4B	ENST00000217402.3	TSL:1 MANE Select	c.386A>T	p.Asp129Val	missense	Exon 3 of 5	ENSP00000217402.2	Q9H444
	CHMP4B	ENST00000873319.1		c.233A>T	p.Asp78Val	missense	Exon 3 of 5	ENSP00000543378.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
1	-	-	Cataract 31 multiple types (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	33
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.88	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Uncertain	0.22	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Uncertain	0.68	D
MutationAssessor	Pathogenic	3.8	H
PhyloP100		9.2
PrimateAI	Uncertain	0.76	T
PROVEAN	Pathogenic	-4.6	D
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0030	D
Sift4G	Uncertain	0.0040	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.88		Loss of disorder (P = 0.0102)
MVP		0.98
MPC		2.7
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.88
gMVP		0.91
Mutation Taster		=13/87	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
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

Other links and lift over

dbSNP: rs118203965; hg19: chr20-32438775;