8-27463477-C-T

Variant names:

• chr8-27463477-C-T
• rs140118184
• NM_000742.4:c.966G>A

Variant summary

Our verdict is Benign. The variant received -16 ACMG points: 0P and 16B. BP4_Strong BP6_Very_Strong BS2

The NM_000742.4(CHRNA2):​c.966G>A​(p.Ser322Ser) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000793 in 1,614,132 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 Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. S322S) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.00027 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000060 (0 hom.)
• Consequence: CHRNA2 NM_000742.4 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:4
• Conservation: PhyloP100: -1.36
• Publications: 1 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
• epilepsy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Benign. The variant received -16 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.55).
• BP6: Variant 8-27463477-C-T is Benign according to our data. Variant chr8-27463477-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 384605.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS2: High AC in GnomAd4 at 41 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000742.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNA2	NM_000742.4	MANE Select	c.966G>A	p.Ser322Ser	synonymous	Exon 6 of 7	NP_000733.2	Q15822-1
	CHRNA2	NM_001282455.2		c.921G>A	p.Ser307Ser	synonymous	Exon 6 of 7	NP_001269384.1	Q15822-2
	CHRNA2	NM_001347705.2		c.489G>A	p.Ser163Ser	synonymous	Exon 6 of 7	NP_001334634.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNA2	ENST00000407991.3	TSL:5 MANE Select	c.966G>A	p.Ser322Ser	synonymous	Exon 6 of 7	ENSP00000385026.1	Q15822-1
	CHRNA2	ENST00000523695.5	TSL:1	n.*368G>A		non_coding_transcript_exon	Exon 6 of 7	ENSP00000430612.1	E5RJ54
	CHRNA2	ENST00000523695.5	TSL:1	n.*368G>A		3_prime_UTR	Exon 6 of 7	ENSP00000430612.1	E5RJ54

Frequencies

GnomAD3 genomes AF: 0.000269 AC: 41 AN: 152134 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000942

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.000478

GnomAD2 exomes AF: 0.0000597 AC: 15 AN: 251446 AF XY: 0.0000294

Gnomad AFR exome AF: 0.000861

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000595 AC: 87 AN: 1461880 Hom.: 0 Cov.: 33 AF XY: 0.0000509 AC XY: 37 AN XY: 727238

African (AFR) AF: 0.000597 AC: 20 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000531 AC: 59 AN: 1112012

Other (OTH) AF: 0.000116 AC: 7 AN: 60396

GnomAD4 genome AF: 0.000269 AC: 41 AN: 152252 Hom.: 0 Cov.: 33 AF XY: 0.000242 AC XY: 18 AN XY: 74440

African (AFR) AF: 0.000939 AC: 39 AN: 41534

American (AMR) AF: 0.00 AC: 0 AN: 15292

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5180

South Asian (SAS) AF: 0.00 AC: 0 AN: 4820

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68024

Other (OTH) AF: 0.000473 AC: 1 AN: 2112

Alfa AF: 0.0000965 Hom.: 0

Bravo AF: 0.000242

ClinVar

ClinVar submissions

Significance: Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	1	Autosomal dominant nocturnal frontal lobe epilepsy (1)
-	-	1	CHRNA2-related disorder (1)
-	-	1	Inborn genetic diseases (1)
-	-	1	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.55
CADD	Benign	10
DANN	Benign	0.91
PhyloP100		-1.4
Mutation Taster		=100/0	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: rs140118184; hg19: chr8-27320994;