rs186593898

Positions:

• chr3-179405258-C-G
• chr3-179405258-C-T

Variant summary

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

The NM_021629.4(GNB4):​c.848G>C​(p.Arg283Pro) 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. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: GNB4 NM_021629.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.83

Genes affected

GNB4 (HGNC:20731): (G protein subunit beta 4) Heterotrimeric guanine nucleotide-binding proteins (G proteins), which integrate signals between receptors and effector proteins, are composed of an alpha, a beta, and a gamma subunit. These subunits are encoded by families of related genes. This gene encodes a beta subunit. Beta subunits are important regulators of alpha subunits, as well as of certain signal transduction receptors and effectors. [provided by RefSeq, Jul 2008]

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, 0.908

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GNB4	NM_021629.4	c.848G>C	p.Arg283Pro	missense_variant	9/10	ENST00000232564.8	NP_067642.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GNB4	ENST00000232564.8	c.848G>C	p.Arg283Pro	missense_variant	9/10	1	NM_021629.4	ENSP00000232564.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease dominant intermediate F Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 11, 2023

This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 283 of the GNB4 protein (p.Arg283Pro). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with GNB4-related conditions. ClinVar contains an entry for this variant (Variation ID: 408271). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt GNB4 protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.18	T;T
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	.;D
M_CAP	Pathogenic	0.47	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Uncertain	0.56	D
MutationAssessor	Pathogenic	4.6	H;H
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-6.4	D;D
REVEL	Pathogenic	0.65
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;D
Vest4		0.96
MutPred		0.60		Loss of glycosylation at S281 (P = 0.0493);Loss of glycosylation at S281 (P = 0.0493);
MVP		0.70
MPC		1.9
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.94
gMVP		0.80

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: rs186593898; hg19: chr3-179123046;