rs199852690

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_000744.7(CHRNA4):​c.1861C>T​(p.Pro621Ser) variant causes a missense change. The variant allele was found at a frequency of 0.000000685 in 1,458,946 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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. P621T) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 missense

Scores

10
8
1

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 6.55

Publications

2 publications found
Variant links:
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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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, 0.884

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CHRNA4NM_000744.7 linkc.1861C>T p.Pro621Ser missense_variant Exon 6 of 6 ENST00000370263.9 NP_000735.1 P43681-1B4DK78Q59FV0
CHRNA4NM_001256573.2 linkc.1333C>T p.Pro445Ser missense_variant Exon 6 of 6 NP_001243502.1 P43681Q4VAQ3B4DK78Q59FV0
CHRNA4NR_046317.2 linkn.2070C>T non_coding_transcript_exon_variant Exon 6 of 6

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
CHRNA4ENST00000370263.9 linkc.1861C>T p.Pro621Ser missense_variant Exon 6 of 6 1 NM_000744.7 ENSP00000359285.4 P43681-1

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD2 exomes
AF:
0.00000407
AC:
1
AN:
245578
AF XY:
0.00000748
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000290
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:
6.85e-7
AC:
1
AN:
1458946
Hom.:
0
Cov.:
32
AF XY:
0.00000138
AC XY:
1
AN XY:
725890
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33452
American (AMR)
AF:
0.00
AC:
0
AN:
44690
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26114
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39690
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86250
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
51034
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5760
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111636
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60320
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
33

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Inborn genetic diseases Uncertain:1
Mar 28, 2024
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The c.1861C>T (p.P621S) alteration is located in exon 6 (coding exon 6) of the CHRNA4 gene. This alteration results from a C to T substitution at nucleotide position 1861, causing the proline (P) at amino acid position 621 to be replaced by a serine (S). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided Uncertain:1
Jan 29, 2025
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.65
BayesDel_addAF
Uncertain
0.12
D
BayesDel_noAF
Uncertain
0.020
CADD
Pathogenic
26
DANN
Pathogenic
1.0
DEOGEN2
Uncertain
0.64
D;.
Eigen
Pathogenic
0.77
Eigen_PC
Pathogenic
0.71
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.96
D;D
M_CAP
Pathogenic
0.38
D
MetaRNN
Pathogenic
0.88
D;D
MetaSVM
Uncertain
0.26
D
MutationAssessor
Uncertain
2.1
M;.
PhyloP100
6.5
PrimateAI
Uncertain
0.68
T
PROVEAN
Pathogenic
-5.5
D;.
REVEL
Pathogenic
0.72
Sift
Pathogenic
0.0
D;.
Sift4G
Uncertain
0.0020
D;D
Polyphen
1.0
D;.
Vest4
0.68
MutPred
0.68
Loss of catalytic residue at P620 (P = 0.0191);.;
MVP
0.88
MPC
1.2
ClinPred
0.99
D
GERP RS
4.4
Varity_R
0.77
gMVP
0.88
Mutation Taster
=45/55
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

Publications

Other links and lift over

dbSNP: rs199852690; hg19: chr20-61978113; API