rs56371471

Variant names:

• chr8-27463458-C-T
• rs56371471
• NM_000742.4:c.985G>A

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BS2

The NM_000742.4(CHRNA2):​c.985G>A​(p.Gly329Ser) variant causes a missense change. The variant allele was found at a frequency of 0.0000062 in 1,613,986 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G329A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: CHRNA2 NM_000742.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.13
• Publications: 2 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: Likely_benign. The variant received -4 ACMG points.

• BS2: High AC in GnomAdExome4 at 8 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.985G>A	p.Gly329Ser	missense	Exon 6 of 7	NP_000733.2	Q15822-1
	CHRNA2	NM_001282455.2		c.940G>A	p.Gly314Ser	missense	Exon 6 of 7	NP_001269384.1	Q15822-2
	CHRNA2	NM_001347705.2		c.508G>A	p.Gly170Ser	missense	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.985G>A	p.Gly329Ser	missense	Exon 6 of 7	ENSP00000385026.1	Q15822-1
	CHRNA2	ENST00000523695.5	TSL:1	n.*387G>A		non_coding_transcript_exon	Exon 6 of 7	ENSP00000430612.1	E5RJ54
	CHRNA2	ENST00000523695.5	TSL:1	n.*387G>A		3_prime_UTR	Exon 6 of 7	ENSP00000430612.1	E5RJ54

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152108 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000483

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461878 Hom.: 0 Cov.: 33 AF XY: 0.00000550 AC XY: 4 AN XY: 727242

African (AFR) AF: 0.00 AC: 0 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: 53404

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

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1112012

Other (OTH) AF: 0.0000497 AC: 3 AN: 60396

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152108 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74306

African (AFR) AF: 0.0000483 AC: 2 AN: 41412

American (AMR) AF: 0.00 AC: 0 AN: 15272

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5182

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10600

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68022

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.0000564 Hom.: 0

Bravo AF: 0.0000189

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	1	-	Autosomal dominant nocturnal frontal lobe epilepsy (1)
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.60
BayesDel_addAF	Uncertain	0.042	T
BayesDel_noAF	Benign	-0.18
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.81	D
Eigen	Uncertain	0.65
Eigen_PC	Uncertain	0.58
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Uncertain	0.92	D
M_CAP	Uncertain	0.095	D
MetaRNN	Uncertain	0.62	D
MetaSVM	Uncertain	0.14	D
MutationAssessor	Pathogenic	2.9	M
PhyloP100		6.1
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-6.0	D
REVEL	Pathogenic	0.65
Sift	Uncertain	0.0090	D
Sift4G	Uncertain	0.016	D
Polyphen		0.97	D
Vest4		0.39
MutPred		0.81		Loss of catalytic residue at I328 (P = 0.295)
MVP		0.92
MPC		0.60
ClinPred		0.99	D
GERP RS		4.0
Varity_R		0.62
gMVP		0.84
Mutation Taster		=43/57	disease causing

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: rs56371471; hg19: chr8-27320975;