rs761335733

Variant names:

• chr20-63350191-G-A
• rs761335733
• NM_000744.7:c.1220C>T

Your query was ambiguous. Multiple possible variants found:

• chr20-63350191-G-A
• chr20-63350191-G-T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_000744.7(CHRNA4):​c.1220C>T​(p.Ser407Phe) variant causes a missense change. The variant allele was found at a frequency of 0.00000138 in 1,444,842 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 (★★). Synonymous variant affecting the same amino acid position (i.e. S407S) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 35)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CHRNA4 NM_000744.7 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 7.17
• Publications: 1 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: Labcorp Genetics (formerly Invitae), G2P
• 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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.36837736).

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.1220C>T	p.Ser407Phe	missense	Exon 5 of 6	NP_000735.1
	CHRNA4	NM_001256573.2		c.692C>T	p.Ser231Phe	missense	Exon 5 of 6	NP_001243502.1
	CHRNA4	NR_046317.2		n.1429C>T		non_coding_transcript_exon	Exon 5 of 6

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNA4	ENST00000370263.9	TSL:1 MANE Select	c.1220C>T	p.Ser407Phe	missense	Exon 5 of 6	ENSP00000359285.4
	CHRNA4	ENST00000463705.5	TSL:1	n.1868C>T		non_coding_transcript_exon	Exon 4 of 5
	CHRNA4	ENST00000467563.3	TSL:1	n.1290C>T		non_coding_transcript_exon	Exon 5 of 6

Frequencies

GnomAD3 genomes Cov.: 35

GnomAD2 exomes AF: 0.00 AC: 0 AN: 224516 AF XY: 0.00

Gnomad AFR exome AF: 0.00

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000138 AC: 2 AN: 1444842 Hom.: 0 Cov.: 76 AF XY: 0.00000140 AC XY: 1 AN XY: 716620

African (AFR) AF: 0.00 AC: 0 AN: 33270

American (AMR) AF: 0.00 AC: 0 AN: 42852

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25702

East Asian (EAS) AF: 0.00 AC: 0 AN: 39058

South Asian (SAS) AF: 0.00 AC: 0 AN: 84762

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 50998

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5740

European-Non Finnish (NFE) AF: 9.07e-7 AC: 1 AN: 1102828

Other (OTH) AF: 0.0000168 AC: 1 AN: 59632

GnomAD4 genome Cov.: 35

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.00000831 AC: 1

ClinVar

ClinVar submissions as Germline

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 specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.013	T
BayesDel_noAF	Benign	-0.22
CADD	Benign	21
DANN	Uncertain	0.99
DEOGEN2	Benign	0.35	T
Eigen	Uncertain	0.22
Eigen_PC	Benign	0.10
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.54	T
M_CAP	Uncertain	0.21	D
MetaRNN	Benign	0.37	T
MetaSVM	Benign	-0.43	T
MutationAssessor	Uncertain	2.6	M
PhyloP100		7.2
PrimateAI	Benign	0.38	T
PROVEAN	Benign	-1.1	N
REVEL	Benign	0.24
Sift	Uncertain	0.010	D
Sift4G	Benign	0.25	T
Polyphen		0.81	P
Vest4		0.47
MutPred		0.25		Loss of phosphorylation at S407 (P = 0.0256)
MVP		0.80
MPC		1.2
ClinPred		0.71	D
GERP RS		4.7
Varity_R		0.19
gMVP		0.32
Mutation Taster		=71/29	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: rs761335733; hg19: chr20-61981543;