NM_000744.7:c.77-10C>T

Variant names:

• chr20-63359709-G-A
• rs200490160
• NM_000744.7:c.77-10C>T

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6_Moderate

The NM_000744.7(CHRNA4):​c.77-10C>T variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000311 in 1,609,956 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 (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 34)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: CHRNA4 NM_000744.7 intron
• Scores: Splicing: ADA: 0.0001953
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.471
• 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: 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: Likely_benign. The variant received -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.81).
• BP6: Variant 20-63359709-G-A is Benign according to our data. Variant chr20-63359709-G-A is described in ClinVar as Likely_benign. ClinVar VariationId is 543549.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNA4	NM_000744.7	c.77-10C>T		intron_variant	Intron 1 of 5	ENST00000370263.9	NP_000735.1
CHRNA4	NM_001256573.2	c.-470-10C>T		intron_variant	Intron 1 of 5		NP_001243502.1
CHRNA4	NR_046317.2	n.261-10C>T		intron_variant	Intron 1 of 5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA4	ENST00000370263.9	c.77-10C>T		intron_variant	Intron 1 of 5	1	NM_000744.7	ENSP00000359285.4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152180 Hom.: 0 Cov.: 34

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

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

GnomAD2 exomes AF: 0.0000122 AC: 3 AN: 246536 AF XY: 0.00000745

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000871

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: 0.00000274 AC: 4 AN: 1457658 Hom.: 0 Cov.: 37 AF XY: 0.00000276 AC XY: 2 AN XY: 725152

African (AFR) AF: 0.00 AC: 0 AN: 33422

American (AMR) AF: 0.0000671 AC: 3 AN: 44690

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26106

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 86162

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51388

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4352

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111698

Other (OTH) AF: 0.00 AC: 0 AN: 60150

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152298 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 74472

African (AFR) AF: 0.00 AC: 0 AN: 41550

American (AMR) AF: 0.0000653 AC: 1 AN: 15308

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3466

East Asian (EAS) AF: 0.00 AC: 0 AN: 5178

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68020

Other (OTH) AF: 0.00 AC: 0 AN: 2116

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal dominant nocturnal frontal lobe epilepsy Benign:1

Jul 19, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.81
CADD	Benign	9.1
DANN	Benign	0.84
PhyloP100		0.47

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00020
dbscSNV1_RF	Benign	0.0060
SpliceAI score (max)		0.030		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: rs200490160; hg19: chr20-61991061;