NM_000748.3:c.7C>G

Variant names:

• chr1-154568051-C-G
• NM_000748.3:c.7C>G

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000748.3(CHRNB2):​c.7C>G​(p.Arg3Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R3W) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CHRNB2 NM_000748.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.93
• Publications: 0 publications found

Genes affected

CHRNB2 (HGNC:1962): (cholinergic receptor nicotinic beta 2 subunit) Neuronal acetylcholine receptors are homo- or heteropentameric complexes composed of homologous alpha and beta subunits. They belong to a superfamily of ligand-gated ion channels which allow the flow of sodium and potassium across the plasma membrane in response to ligands such as acetylcholine and nicotine. This gene encodes one of several beta subunits. Mutations in this gene are associated with autosomal dominant nocturnal frontal lobe epilepsy. [provided by RefSeq, Jul 2008]

CHRNB2 Gene-Disease associations (from GenCC):

• familial sleep-related hypermotor epilepsy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• autosomal dominant nocturnal frontal lobe epilepsy 3

  Inheritance: AD Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• autosomal dominant nocturnal frontal lobe epilepsy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000286391 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.044729114).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNB2	NM_000748.3	c.7C>G	p.Arg3Gly	missense_variant	Exon 1 of 6	ENST00000368476.4	NP_000739.1
CHRNB2	XR_001736952.3	n.274C>G		non_coding_transcript_exon_variant	Exon 1 of 7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNB2	ENST00000368476.4	c.7C>G	p.Arg3Gly	missense_variant	Exon 1 of 6	1	NM_000748.3	ENSP00000357461.3

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

Inborn genetic diseases Uncertain:1

Apr 03, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.7C>G (p.R3G) alteration is located in exon 1 (coding exon 1) of the CHRNB2 gene. This alteration results from a C to G substitution at nucleotide position 7, causing the arginine (R) at amino acid position 3 to be replaced by a glycine (G). 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	Benign	0.066
BayesDel_addAF	Benign	-0.17	T
BayesDel_noAF	Benign	-0.49
CADD	Benign	7.4
DANN	Benign	0.88
DEOGEN2	Benign	0.31	T;.
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.5
FATHMM_MKL	Benign	0.0022	N
LIST_S2	Benign	0.37	T;T
M_CAP	Benign	0.032	D
MetaRNN	Benign	0.045	T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	-0.90	N;.
PhyloP100		-1.9
PrimateAI	Benign	0.28	T
PROVEAN	Benign	-0.96	N;.
REVEL	Benign	0.23
Sift	Benign	0.34	T;.
Sift4G	Benign	0.41	T;.
Polyphen		0.0	B;.
Vest4		0.11
MutPred		0.33		Loss of stability (P = 0.0316);Loss of stability (P = 0.0316);
MVP		0.62
MPC		1.4
ClinPred		0.11	T
GERP RS		-8.4
PromoterAI		0.097	Neutral
Varity_R		0.057
gMVP		0.55
Mutation Taster		=92/8	polymorphism

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

Other links and lift over

hg19: chr1-154540527;