rs869312826

chr1-1787378-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP5_Moderate

The NM_002074.5(GNB1):c.976G>A(p.Ala326Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A326D) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GNB1 NM_002074.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:3
• Conservation: PhyloP100: 7.73

Genes affected

GNB1 (HGNC:4396): (G protein subunit beta 1) 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. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2013]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, GNB1
• PP5: Variant 1-1787378-C-T is Pathogenic according to our data. Variant chr1-1787378-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 224718.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr1-1787378-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GNB1	NM_002074.5	c.976G>A	p.Ala326Thr	missense_variant	11/12	ENST00000378609.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GNB1	ENST00000378609.9	c.976G>A	p.Ala326Thr	missense_variant	11/12	1	NM_002074.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, single submitter

Submissions by phenotype

Intellectual disability, autosomal dominant 42 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Feb 02, 2022

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Likely pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with GNB1-related neurodevelopmental disorder (MIM#616973). However, a dominant-negative disease mechanism has not been excluded (PMID: 28087732, 32918542). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0115 - Variants in this gene are known to have variable expressivity. Phenotypes reported to have variability include epilepsy/seizures and brain abnormalities (PMID: 32918542). (I) 0200 - Variant is predicted to result in a missense amino acid change from alanine to threonine. (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0502 - Missense variant with conflicting in silico predictions and uninformative conservation. (I) 0603 - Missense variant in a region that is highly intolerant to missense variation (high constraint region in DECIPHER). (SP) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0803 - This variant has limited previous evidence of pathogenicity in unrelated individuals. This variant has been observed in two individuals with GNB1 -related conditions (PMIDs: 29694806, 27108799). (SP) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Hypotonia;C0036572:Seizure;na:Neurodevelopmental Disability Pathogenic:1

Likely pathogenic, no assertion criteria provided

research

University of Washington Center for Mendelian Genomics, University of Washington

May 05, 2016

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Hypotonia;C0036572:Seizure;C0494475:Bilateral tonic-clonic seizure;C0557874:Global developmental delay;C3714756:Intellectual disability Pathogenic:1

Pathogenic, no assertion criteria provided

research

Genomics And Bioinformatics Analysis Resource, Columbia University

Feb 10, 2016

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
Cadd	Pathogenic	29
Dann	Pathogenic	1.0
DEOGEN2	Benign	0.38	T;T;T
Eigen	Uncertain	0.39
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;.
M_CAP	Benign	0.047	D
MetaRNN	Uncertain	0.62	D;D;D
MetaSVM	Benign	-0.89	T
MutationAssessor	Benign	0.75	N;.;N
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.86	D
Sift4G	Uncertain	0.030	D;T;D
Polyphen		1.0	D;.;D
Vest4		0.67
MutPred		0.50		Gain of disorder (P = 0.2702);.;Gain of disorder (P = 0.2702);
MVP		0.75
MPC		2.8
ClinPred		0.98	D
GERP RS		5.7
Varity_R		0.91
gMVP		0.74

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: rs869312826; hg19: chr1-1718817;