chr1-154568061-G-A

Variant names:

• chr1-154568061-G-A
• rs1304588530
• NM_000748.3:c.17G>A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000748.3(CHRNB2):​c.17G>A​(p.Gly6Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000069 in 1,448,868 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. G6G) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: CHRNB2 NM_000748.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.429

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.10380739).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNB2	NM_000748.3	c.17G>A	p.Gly6Asp	missense_variant	Exon 1 of 6	ENST00000368476.4	NP_000739.1
CHRNB2	XR_001736952.3	n.284G>A		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.17G>A	p.Gly6Asp	missense_variant	Exon 1 of 6	1	NM_000748.3	ENSP00000357461.3
CHRNB2	ENST00000637900.1	c.17G>A	p.Gly6Asp	missense_variant	Exon 1 of 6	5		ENSP00000490474.1
CHRNB2	ENST00000636034.1	n.17G>A		non_coding_transcript_exon_variant	Exon 1 of 9	5		ENSP00000489703.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000464 AC: 1 AN: 215398 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 118828

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: 0.0000107

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.90e-7 AC: 1 AN: 1448868 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 719842

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.03e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal dominant nocturnal frontal lobe epilepsy Uncertain:1

Sep 20, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine with aspartic acid at codon 6 of the CHRNB2 protein (p.Gly6Asp). The glycine residue is weakly conserved and there is a moderate physicochemical difference between glycine and aspartic acid. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with CHRNB2-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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	Benign	0.17
BayesDel_addAF	Uncertain	0.016	T
BayesDel_noAF	Benign	-0.21
CADD	Benign	23
DANN	Benign	0.93
DEOGEN2	Benign	0.21	T;.
Eigen	Benign	-0.74
Eigen_PC	Benign	-0.71
FATHMM_MKL	Benign	0.014	N
LIST_S2	Benign	0.54	T;T
M_CAP	Benign	0.023	T
MetaRNN	Benign	0.10	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.5	L;.
PrimateAI	Benign	0.48	T
PROVEAN	Benign	-0.28	N;.
REVEL	Uncertain	0.36
Sift	Benign	0.14	T;.
Sift4G	Benign	0.53	T;.
Polyphen		0.0020	B;.
Vest4		0.32
MVP		0.96
MPC		1.4
ClinPred		0.066	T
GERP RS		1.1
Varity_R		0.057
gMVP		0.57

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: rs1304588530; hg19: chr1-154540537;