chr8-42732009-A-C

Position:

• chr8-42732009-A-C

Variant summary

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

The NM_000749.5(CHRNB3):​c.702A>C​(p.Leu234Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: CHRNB3 NM_000749.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.0280

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CHRNB3	NM_000749.5	c.702A>C	p.Leu234Phe	missense_variant	5/6	ENST00000289957.3	NP_000740.1
CHRNB3	NM_001347717.2	c.480A>C	p.Leu160Phe	missense_variant	6/7		NP_001334646.1
CHRNB3	XM_011544390.3	c.315A>C	p.Leu105Phe	missense_variant	3/4		XP_011542692.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHRNB3	ENST00000289957.3	c.702A>C	p.Leu234Phe	missense_variant	5/6	1	NM_000749.5	ENSP00000289957	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 21, 2021

The c.702A>C (p.L234F) alteration is located in exon 5 (coding exon 5) of the CHRNB3 gene. This alteration results from a A to C substitution at nucleotide position 702, causing the leucine (L) at amino acid position 234 to be replaced by a phenylalanine (F). 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	Pathogenic	0.57
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Benign	17
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.67	D
Eigen	Benign	0.038
Eigen_PC	Benign	-0.12
FATHMM_MKL	Benign	0.65	D
LIST_S2	Benign	0.79	T
M_CAP	Uncertain	0.12	D
MetaRNN	Uncertain	0.63	D
MetaSVM	Uncertain	-0.021	T
MutationAssessor	Uncertain	2.3	M
MutationTaster	Benign	1.0	D
PrimateAI	Benign	0.48	T
PROVEAN	Uncertain	-3.8	D
REVEL	Pathogenic	0.70
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.39
MutPred		0.70		Loss of methylation at R230 (P = 0.2555);
MVP		0.78
MPC		0.89
ClinPred		0.98	D
GERP RS		1.8
Varity_R		0.47
gMVP		0.81

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr8-42587152;