rs1568805215

Variant names:

• chr20-63346768-G-C
• rs1568805215
• NM_000744.7:c.1854C>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000744.7(CHRNA4):​c.1854C>G​(p.Phe618Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: CHRNA4 NM_000744.7 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 0.732
• Publications: 0 publications found

Genes affected

CHRNA4 (HGNC:1958): (cholinergic receptor nicotinic alpha 4 subunit) This gene encodes a nicotinic acetylcholine receptor, which belongs to a superfamily of ligand-gated ion channels that play a role in fast signal transmission at synapses. These pentameric receptors can bind acetylcholine, which causes an extensive change in conformation that leads to the opening of an ion-conducting channel across the plasma membrane. This protein is an integral membrane receptor subunit that can interact with either nAChR beta-2 or nAChR beta-4 to form a functional receptor. Mutations in this gene cause nocturnal frontal lobe epilepsy type 1. Polymorphisms in this gene that provide protection against nicotine addiction have been described. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2012]

CHRNA4 Gene-Disease associations (from GenCC):

• autosomal dominant nocturnal frontal lobe epilepsy 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• familial sleep-related hypermotor epilepsy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• autosomal dominant nocturnal frontal lobe epilepsy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.859

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000744.7. 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
	CHRNA4	NM_000744.7	MANE Select	c.1854C>G	p.Phe618Leu	missense	Exon 6 of 6	NP_000735.1	P43681-1
	CHRNA4	NM_001256573.2		c.1326C>G	p.Phe442Leu	missense	Exon 6 of 6	NP_001243502.1	Q4VAQ3
	CHRNA4	NR_046317.2		n.2063C>G		non_coding_transcript_exon	Exon 6 of 6

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNA4	ENST00000370263.9	TSL:1 MANE Select	c.1854C>G	p.Phe618Leu	missense	Exon 6 of 6	ENSP00000359285.4	P43681-1
	CHRNA4	ENST00000463705.5	TSL:1	n.2502C>G		non_coding_transcript_exon	Exon 5 of 5
	CHRNA4	ENST00000467563.3	TSL:1	n.1924C>G		non_coding_transcript_exon	Exon 6 of 6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

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	-	Inborn genetic diseases (1)
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.060
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.66	D
Eigen	Uncertain	0.47
Eigen_PC	Uncertain	0.43
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.53	D
MetaRNN	Pathogenic	0.86	D
MetaSVM	Uncertain	0.44	D
MutationAssessor	Uncertain	2.5	M
PhyloP100		0.73
PrimateAI	Uncertain	0.70	T
PROVEAN	Uncertain	-4.0	D
REVEL	Pathogenic	0.73
Sift	Benign	0.037	D
Sift4G	Benign	0.085	T
Polyphen		1.0	D
Vest4		0.75
MutPred		0.61		Gain of glycosylation at P621 (P = 0.1258)
MVP		0.87
MPC		1.3
ClinPred		0.99	D
GERP RS		4.4
Varity_R		0.49
gMVP		0.84
Mutation Taster		=55/45	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: rs1568805215; hg19: chr20-61978120;