20-63355996-G-C

Variant names:

• chr20-63355996-G-C
• rs377114983
• NM_000744.7:c.362C>G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_000744.7(CHRNA4):​c.362C>G​(p.Pro121Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,510 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CHRNA4 NM_000744.7 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.76

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNA4	NM_000744.7	c.362C>G	p.Pro121Arg	missense_variant	Exon 4 of 6	ENST00000370263.9	NP_000735.1
CHRNA4	NM_001256573.2	c.-185C>G		5_prime_UTR_variant	Exon 4 of 6		NP_001243502.1
CHRNA4	NR_046317.2	n.571C>G		non_coding_transcript_exon_variant	Exon 4 of 6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA4	ENST00000370263.9	c.362C>G	p.Pro121Arg	missense_variant	Exon 4 of 6	1	NM_000744.7	ENSP00000359285.4

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 249784 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135588

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000889

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460510 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726556

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 30

ExAC AF: 0.00000827 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.91	D
Eigen	Uncertain	0.53
Eigen_PC	Uncertain	0.51
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.56	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Uncertain	0.35	D
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-8.3	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.93		Loss of stability (P = 0.0758);
MVP		0.97
MPC		1.3
ClinPred		1.0	D
GERP RS		4.3
Varity_R		0.84
gMVP		0.96

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs377114983; hg19: chr20-61987348;