8-27463773-C-T
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Variant summary
Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2BP4
The NM_000742.4(CHRNA2):c.670G>A(p.Asp224Asn) variant causes a missense change. The variant allele was found at a frequency of 0.00000274 in 1,461,888 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).
Frequency
Genomes: not found (cov: 32)
Exomes 𝑓: 0.0000027 ( 0 hom. )
Consequence
CHRNA2
NM_000742.4 missense
NM_000742.4 missense
Scores
11
8
Clinical Significance
Conservation
PhyloP100: 6.01
Genes affected
CHRNA2 (HGNC:1956): (cholinergic receptor nicotinic alpha 2 subunit) Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels formed by a pentameric arrangement of alpha and beta subunits to create distinct muscle and neuronal receptors. Neuronal receptors are found throughout the peripheral and central nervous system where they are involved in fast synaptic transmission. This gene encodes an alpha subunit that is widely expressed in the brain. The proposed structure for nAChR subunits is a conserved N-terminal extracellular domain followed by three conserved transmembrane domains, a variable cytoplasmic loop, a fourth conserved transmembrane domain, and a short C-terminal extracellular region. Mutations in this gene cause autosomal dominant nocturnal frontal lobe epilepsy type 4. Single nucleotide polymorphisms (SNPs) in this gene have been associated with nicotine dependence. [provided by RefSeq, Nov 2009]
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ACMG classification
Classification made for transcript
Verdict is Uncertain_significance. Variant got 1 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (MetaRNN=0.3456729).
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
CHRNA2 | NM_000742.4 | c.670G>A | p.Asp224Asn | missense_variant | 6/7 | ENST00000407991.3 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
CHRNA2 | ENST00000407991.3 | c.670G>A | p.Asp224Asn | missense_variant | 6/7 | 5 | NM_000742.4 | P2 |
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD3 genomes
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32
GnomAD3 exomes AF: 0.0000119 AC: 3AN: 251484Hom.: 0 AF XY: 0.00000736 AC XY: 1AN XY: 135918
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GnomAD4 exome AF: 0.00000274 AC: 4AN: 1461888Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1AN XY: 727246
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GnomAD4 genome Cov.: 32
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32
ExAC
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ClinVar
Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link
Submissions by phenotype
Autosomal dominant nocturnal frontal lobe epilepsy Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Invitae | May 14, 2019 | This sequence change replaces aspartic acid with asparagine at codon 224 of the CHRNA2 protein (p.Asp224Asn). The aspartic acid residue is moderately conserved and there is a small physicochemical difference between aspartic acid and asparagine. This variant is present in population databases (rs781326114, ExAC 0.009%). This variant has not been reported in the literature in individuals with CHRNA2-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:
Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
BayesDel_addAF
Benign
T
BayesDel_noAF
Benign
CADD
Uncertain
DANN
Uncertain
DEOGEN2
Uncertain
D;.;.
Eigen
Uncertain
Eigen_PC
Uncertain
FATHMM_MKL
Uncertain
D
LIST_S2
Uncertain
D;D;D
M_CAP
Benign
D
MetaRNN
Benign
T;T;T
MetaSVM
Uncertain
T
MutationAssessor
Benign
N;.;.
MutationTaster
Benign
D;D;D
PrimateAI
Uncertain
T
PROVEAN
Uncertain
D;.;D
REVEL
Uncertain
Sift
Uncertain
D;.;D
Sift4G
Benign
T;T;T
Polyphen
B;.;.
Vest4
MutPred
Loss of ubiquitination at K223 (P = 0.1083);.;.;
MVP
MPC
ClinPred
D
GERP RS
Varity_R
gMVP
Splicing
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SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at