18-11851905-A-T

Variant names:

• chr18-11851905-A-T
• rs775796754
• NM_020412.5:c.394A>T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_020412.5(CHMP1B):​c.394A>T​(p.Met132Leu) 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 benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 33)
• Consequence: CHMP1B NM_020412.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 8.95

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:52778): (CHMP1B antisense RNA 1)

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.3145793).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHMP1B	NM_020412.5	c.394A>T	p.Met132Leu	missense_variant	Exon 1 of 1	ENST00000526991.3	NP_065145.2
GNAL	NM_182978.4	c.723-10490A>T		intron_variant	Intron 5 of 11	ENST00000334049.11	NP_892023.1
GNAL	NM_001369387.1	c.492-10490A>T		intron_variant	Intron 5 of 11	ENST00000423027.8	NP_001356316.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHMP1B	ENST00000526991.3	c.394A>T	p.Met132Leu	missense_variant	Exon 1 of 1	6	NM_020412.5	ENSP00000432279.1
GNAL	ENST00000334049.11	c.723-10490A>T		intron_variant	Intron 5 of 11	1	NM_182978.4	ENSP00000334051.5
GNAL	ENST00000423027.8	c.492-10490A>T		intron_variant	Intron 5 of 11	1	NM_001369387.1	ENSP00000408489.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000401 AC: 1 AN: 249210 Hom.: 0 AF XY: 0.00000740 AC XY: 1 AN XY: 135206

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: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000885

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000826 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.41
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.030
CADD	Uncertain	25
DANN	Benign	0.96
DEOGEN2	Uncertain	0.56	D
Eigen	Uncertain	0.20
Eigen_PC	Uncertain	0.31
FATHMM_MKL	Uncertain	0.86	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Benign	0.040	D
MetaRNN	Benign	0.31	T
MetaSVM	Benign	-0.55	T
PrimateAI	Uncertain	0.76	T
PROVEAN	Uncertain	-2.6	D
REVEL	Benign	0.24
Sift	Benign	0.092	T
Sift4G	Benign	0.27	T
Polyphen		0.035	B
Vest4		0.52
MutPred		0.51		Loss of phosphorylation at T135 (P = 0.1618);
MVP		0.95
MPC		0.69
ClinPred		0.68	D
GERP RS		5.6
Varity_R		0.55
gMVP		0.66

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

Other links and lift over

dbSNP: rs775796754; hg19: chr18-11851904;