rs387907341

chr3-179416495-T-Cchr3-179416495-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Moderate PP5_Moderate

The NM_021629.4(GNB4):c.265A>G(p.Lys89Glu) variant causes a missense, splice region 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. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K89Q) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GNB4 NM_021629.4 missense, splice_region
• Scores: Splicing: ADA: 0.6880
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.91

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a repeat WD 1 (size 39) in uniprot entity GBB4_HUMAN there are 7 pathogenic changes around while only 2 benign (78%) in NM_021629.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.872
• PP5: Variant 3-179416495-T-C is Pathogenic according to our data. Variant chr3-179416495-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 41941.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr3-179416495-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GNB4	NM_021629.4	c.265A>G	p.Lys89Glu	missense_variant, splice_region_variant	5/10	ENST00000232564.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GNB4	ENST00000232564.8	c.265A>G	p.Lys89Glu	missense_variant, splice_region_variant	5/10	1	NM_021629.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 22

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease dominant intermediate F Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Oct 18, 2022	For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this missense change affects GNB4 function (PMID: 23434117). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 41941). This missense change has been observed in individual(s) with Charcot-Marie-Tooth disease (PMID: 23434117, 31211173, 34071515). In at least one individual the variant was observed to be de novo. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces lysine, which is basic and polar, with glutamic acid, which is acidic and polar, at codon 89 of the GNB4 protein (p.Lys89Glu). -
Pathogenic, no assertion criteria provided	literature only	OMIM	Mar 07, 2013	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
Cadd	Pathogenic	33
Dann	Uncertain	1.0
DEOGEN2	Benign	0.22	T;T
Eigen	Pathogenic	0.73
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.29	D
MetaRNN	Pathogenic	0.87	D;D
MetaSVM	Benign	-0.99	T
MutationAssessor	Uncertain	2.2	M;M
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.90	D
PROVEAN	Uncertain	-3.7	D;D
REVEL	Uncertain	0.50
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.0020	D;D
Polyphen		1.0	D;D
Vest4		0.94
MutPred		0.59		Loss of ubiquitination at K89 (P = 0.0446);Loss of ubiquitination at K89 (P = 0.0446);
MVP		0.80
MPC		0.88
ClinPred		0.99	D
GERP RS		5.5
Varity_R		0.86
gMVP		0.64

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.69
dbscSNV1_RF	Benign	0.48
SpliceAI score (max)		0.010		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: rs387907341; hg19: chr3-179134283;