chr8-27468423-G-A

Variant names:

• chr8-27468423-G-A
• rs2565062
• NM_000742.4:c.339+912C>T

Variant summary

Our verdict is Benign. The variant received -12 ACMG points: 0P and 12B. BP4_Strong BA1

The NM_000742.4(CHRNA2):​c.339+912C>T variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.17 in 152,236 control chromosomes in the GnomAD database, including 2,546 homozygotes. 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: 𝑓 0.17 (2546 hom., cov: 33)
• Consequence: CHRNA2 NM_000742.4 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.765
• Publications: 5 publications found

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]

CHRNA2 Gene-Disease associations (from GenCC):

• autosomal dominant nocturnal frontal lobe epilepsy 4

  Inheritance: AD Classification: STRONG, LIMITED Submitted by: G2P, Illumina, Labcorp Genetics (formerly Invitae)
• autosomal dominant nocturnal frontal lobe epilepsy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial sleep-related hypermotor epilepsy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• benign familial infantile epilepsy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Benign. The variant received -12 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.91).
• BA1: GnomAd4 highest subpopulation (EAS) allele frequency at 95% confidence interval = 0.426 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNA2	NM_000742.4	c.339+912C>T		intron_variant	Intron 4 of 6	ENST00000407991.3	NP_000733.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA2	ENST00000407991.3	c.339+912C>T		intron_variant	Intron 4 of 6	5	NM_000742.4	ENSP00000385026.1

Frequencies

GnomAD3 genomes AF: 0.170 AC: 25869 AN: 152118 Hom.: 2539 Cov.: 33

Gnomad AFR AF: 0.208

Gnomad AMI AF: 0.125

Gnomad AMR AF: 0.183

Gnomad ASJ AF: 0.0548

Gnomad EAS AF: 0.441

Gnomad SAS AF: 0.147

Gnomad FIN AF: 0.165

Gnomad MID AF: 0.0601

Gnomad NFE AF: 0.134

Gnomad OTH AF: 0.141

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome AF: 0.170 AC: 25907 AN: 152236 Hom.: 2546 Cov.: 33 AF XY: 0.174 AC XY: 12923 AN XY: 74442

African (AFR) AF: 0.208 AC: 8648 AN: 41532

American (AMR) AF: 0.183 AC: 2803 AN: 15290

Ashkenazi Jewish (ASJ) AF: 0.0548 AC: 190 AN: 3470

East Asian (EAS) AF: 0.441 AC: 2285 AN: 5180

South Asian (SAS) AF: 0.148 AC: 715 AN: 4824

European-Finnish (FIN) AF: 0.165 AC: 1747 AN: 10614

Middle Eastern (MID) AF: 0.0646 AC: 19 AN: 294

European-Non Finnish (NFE) AF: 0.134 AC: 9091 AN: 68008

Other (OTH) AF: 0.140 AC: 295 AN: 2114

Alfa AF: 0.153 Hom.: 334

Bravo AF: 0.173

Asia WGS AF: 0.269 AC: 934 AN: 3478

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.91
CADD	Benign	0.20
DANN	Benign	0.49
PhyloP100		-0.77
Mutation Taster		=100/0	polymorphism (auto)

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: rs2565062; hg19: chr8-27325940;