chr8-42697490-G-T

Variant names:

• chr8-42697490-G-T
• rs4950
• NM_000749.5:c.-57G>T

Variant summary

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

The NM_000749.5(CHRNB3):​c.-57G>T variant causes a 5 prime UTR premature start codon gain 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 31)
• Consequence: CHRNB3 NM_000749.5 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.266
• Publications: 64 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]

LOC124900250 (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 (BayesDel_noAF=-0.83).

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNB3	NM_000749.5	MANE Select	c.-57G>T		5_prime_UTR_premature_start_codon_gain	Exon 1 of 6	NP_000740.1
	CHRNB3	NM_000749.5	MANE Select	c.-57G>T		5_prime_UTR	Exon 1 of 6	NP_000740.1
	CHRNB3	NM_001347717.2		c.-412G>T		5_prime_UTR_premature_start_codon_gain	Exon 1 of 7	NP_001334646.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNB3	ENST00000289957.3	TSL:1 MANE Select	c.-57G>T		5_prime_UTR_premature_start_codon_gain	Exon 1 of 6	ENSP00000289957.2
	CHRNB3	ENST00000289957.3	TSL:1 MANE Select	c.-57G>T		5_prime_UTR	Exon 1 of 6	ENSP00000289957.2
	CHRNB3	ENST00000534391.1	TSL:3	c.-412G>T		5_prime_UTR_premature_start_codon_gain	Exon 1 of 4	ENSP00000433913.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 18

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.83
CADD	Benign	0.47
DANN	Benign	0.53
PhyloP100		0.27
PromoterAI		0.0036	Neutral
Mutation Taster		=300/0	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

dbSNP: rs4950; hg19: chr8-42552633;