chr8-42708756-C-A

Variant names:

• chr8-42708756-C-A
• rs1334592295
• NM_000749.5:c.92C>A

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_000749.5(CHRNB3):​c.92C>A​(p.Ala31Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,728 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CHRNB3 NM_000749.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.70
• Publications: 0 publications found

Genes affected

CHRNB3 (HGNC:1963): (cholinergic receptor nicotinic beta 3 subunit) The nicotinic acetylcholine receptors (nAChRs) are members of a superfamily of ligand-gated ion channels that mediate fast signal transmission at synapses. The nAChRs are (hetero)pentamers composed of homologous subunits. The subunits that make up the muscle and neuronal forms of nAChRs are encoded by separate genes and have different primary structure. There are several subtypes of neuronal nAChRs that vary based on which homologous subunits are arranged around the central channel. They are classified as alpha-subunits if, like muscle alpha-1 (MIM 100690), they have a pair of adjacent cysteines as part of the presumed acetylcholine binding site. Subunits lacking these cysteine residues are classified as beta-subunits (Groot Kormelink and Luyten, 1997 [PubMed 9009220]). Elliott et al. (1996) [PubMed 8906617] stated that the proposed structure for each subunit is a conserved N-terminal extracellular domain followed by 3 conserved transmembrane domains, a variable cytoplasmic loop, a fourth conserved transmembrane domain, and a short C-terminal extracellular region.[supplied by OMIM, Apr 2010]

ENSG00000255101 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000749.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNB3	NM_000749.5	MANE Select	c.92C>A	p.Ala31Asp	missense	Exon 2 of 6	NP_000740.1	Q05901
	CHRNB3	NM_001347717.2		c.-131C>A		5_prime_UTR	Exon 3 of 7	NP_001334646.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNB3	ENST00000289957.3	TSL:1 MANE Select	c.92C>A	p.Ala31Asp	missense	Exon 2 of 6	ENSP00000289957.2	Q05901
	CHRNB3	ENST00000534391.1	TSL:3	c.-131C>A		5_prime_UTR	Exon 3 of 4	ENSP00000433913.1	A0A1D5RMT8
	CHRNB3	ENST00000531610.5	TSL:4	n.512C>A		splice_region non_coding_transcript_exon	Exon 4 of 4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251266 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461728 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727152

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.0000447 AC: 2 AN: 44712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86216

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111920

Other (OTH) AF: 0.00 AC: 0 AN: 60392

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000000770867), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.17	T
BayesDel_noAF	Benign	-0.40
CADD	Benign	21
DANN	Uncertain	1.0
DEOGEN2	Benign	0.13	T
Eigen	Uncertain	0.37
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Benign	0.65	D
LIST_S2	Benign	0.71	T
M_CAP	Benign	0.011	T
MetaRNN	Uncertain	0.51	D
MetaSVM	Benign	-0.92	T
MutationAssessor	Benign	0.54	N
PhyloP100		2.7
PrimateAI	Uncertain	0.50	T
PROVEAN	Benign	-0.72	N
REVEL	Benign	0.19
Sift	Benign	0.17	T
Sift4G	Benign	0.080	T
Polyphen		0.99	D
Vest4		0.48
MutPred		0.62		Gain of disorder (P = 0.0387)
MVP		0.59
MPC		0.39
ClinPred		0.42	T
GERP RS		5.7
Varity_R		0.27
gMVP		0.55
Mutation Taster		=60/40	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
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

Other links and lift over

dbSNP: rs1334592295; hg19: chr8-42563899;