18-11851857-G-T

Position:

• chr18-11851857-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_020412.5(CHMP1B):​c.346G>T​(p.Asp116Tyr) 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: CHMP1B NM_020412.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.60

Genes affected

CHMP1B (HGNC:24287): (charged multivesicular body protein 1B) CHMP1B belongs to the chromatin-modifying protein/charged multivesicular body protein (CHMP) family. These proteins are components of ESCRT-III (endosomal sorting complex required for transport III), a complex involved in degradation of surface receptor proteins and formation of endocytic multivesicular bodies (MVBs). Some CHMPs have both nuclear and cytoplasmic/vesicular distributions, and one such CHMP, CHMP1A (MIM 164010), is required for both MVB formation and regulation of cell cycle progression (Tsang et al., 2006 [PubMed 16730941]).[supplied by OMIM, Mar 2008]

GNAL (HGNC:4388): (G protein subunit alpha L) This gene encodes a stimulatory G protein alpha subunit which mediates odorant signaling in the olfactory epithelium. This protein couples dopamine type 1 receptors and adenosine A2A receptors and is widely expressed in the central nervous system. Mutations in this gene have been associated with dystonia 25 and this gene is located in a susceptibility region for bipolar disorder and schizophrenia. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2013]

CHMP1B-AS1 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.905

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CHMP1B	NM_020412.5	c.346G>T	p.Asp116Tyr	missense_variant	1/1	ENST00000526991.3	NP_065145.2
GNAL	NM_182978.4	c.723-10538G>T		intron_variant		ENST00000334049.11	NP_892023.1
GNAL	NM_001369387.1	c.492-10538G>T		intron_variant		ENST00000423027.8	NP_001356316.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHMP1B	ENST00000526991.3	c.346G>T	p.Asp116Tyr	missense_variant	1/1	6	NM_020412.5	ENSP00000432279.1
GNAL	ENST00000334049.11	c.723-10538G>T		intron_variant		1	NM_182978.4	ENSP00000334051.5
GNAL	ENST00000423027.8	c.492-10538G>T		intron_variant		1	NM_001369387.1	ENSP00000408489.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 10, 2024

The c.346G>T (p.D116Y) alteration is located in exon 1 (coding exon 1) of the CHMP1B gene. This alteration results from a G to T substitution at nucleotide position 346, causing the aspartic acid (D) at amino acid position 116 to be replaced by a tyrosine (Y). 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	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.80	D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Uncertain	0.17	D
MetaRNN	Pathogenic	0.90	D
MetaSVM	Uncertain	0.69	D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-8.1	D
REVEL	Pathogenic	0.83
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.83
MutPred		0.63		Loss of disorder (P = 0.016);
MVP		0.93
MPC		1.7
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.94
gMVP		0.89

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr18-11851856;