8-42732516-G-T

Position:

• chr8-42732516-G-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_000749.5(CHRNB3):​c.1209G>T​(p.Ser403Ser) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000207 in 1,452,248 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CHRNB3 NM_000749.5 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -1.21

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 Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.87).
• BP7: Synonymous conserved (PhyloP=-1.21 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CHRNB3	NM_000749.5	c.1209G>T	p.Ser403Ser	synonymous_variant	5/6	ENST00000289957.3	NP_000740.1
CHRNB3	NM_001347717.2	c.987G>T	p.Ser329Ser	synonymous_variant	6/7		NP_001334646.1
CHRNB3	XM_011544390.3	c.822G>T	p.Ser274Ser	synonymous_variant	3/4		XP_011542692.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHRNB3	ENST00000289957.3	c.1209G>T	p.Ser403Ser	synonymous_variant	5/6	1	NM_000749.5	ENSP00000289957.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000417 AC: 1 AN: 239538 Hom.: 0 AF XY: 0.00000770 AC XY: 1 AN XY: 129888

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: 0.00000919

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000207 AC: 3 AN: 1452248 Hom.: 0 Cov.: 32 AF XY: 0.00000277 AC XY: 2 AN XY: 722096

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.87
CADD	Benign	0.29
DANN	Benign	0.40

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

Publications

LitVar

Other links and lift over

dbSNP: rs4953; hg19: chr8-42587659;