Genetic Variant CHRNA1:p.Arg75Leu (chr2-174759341-C-A) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2PP2PP3

The NM_000079.4(CHRNA1):c.224G>T(p.Arg75Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R75H) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 31)

Consequence

CHRNA1
NM_000079.4 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.88

Publications

5 publications found

Variant links:

Genes affected

CHRNA1 (HGNC:1955): (cholinergic receptor nicotinic alpha 1 subunit) The muscle acetylcholine receptor consiststs of 5 subunits of 4 different types: 2 alpha subunits and 1 each of the beta, gamma, and delta subunits. This gene encodes an alpha subunit that plays a role in acetlycholine binding/channel gating. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Nov 2012]

CHRNA1 Gene-Disease associations (from GenCC):

congenital myasthenic syndrome 1A
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
myasthenic syndrome, congenital, 1B, fast-channel
Inheritance: AD, AR Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
lethal multiple pterygium syndrome
Inheritance: AR Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), Orphanet
postsynaptic congenital myasthenic syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

CHRNA1 links:

ENSG00000236449 (HGNC:):

ENSG00000236449 links:

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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;

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 16 curated pathogenic missense variants (we use a threshold of 10). The gene has 5 curated benign missense variants. Gene score misZ: 0.72157 (below the threshold of 3.09). Trascript score misZ: 1.6771 (below the threshold of 3.09). GenCC associations: The gene is linked to lethal multiple pterygium syndrome, congenital myasthenic syndrome 1A, myasthenic syndrome, congenital, 1B, fast-channel, postsynaptic congenital myasthenic syndrome.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.823

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000079.4. 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
	CHRNA1	NM_000079.4	MANE Select	c.224G>T	p.Arg75Leu	missense	Exon 3 of 9	NP_000070.1	Q53SH4
	CHRNA1	NM_001039523.3		c.224G>T	p.Arg75Leu	missense	Exon 3 of 10	NP_001034612.1	P02708-1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
CHRNA1	ENST00000348749.9	TSL:1 MANE Select	c.224G>T	p.Arg75Leu	missense	Exon 3 of 9	ENSP00000261008.5	P02708-2
CHRNA1	ENST00000409323.1	TSL:1	c.224G>T	p.Arg75Leu	missense	Exon 3 of 6	ENSP00000386684.1	G5E9G9
ENSG00000236449	ENST00000442996.1	TSL:1	n.322-13408C>A		intron	N/A

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251460

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Cov.:

GnomAD4 genome

Cov.:

ExAC

AF:

0.00000824

AC:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.66

BayesDel_addAF

Pathogenic

0.24

BayesDel_noAF

Pathogenic

0.28

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.32

Eigen

Pathogenic

0.81

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.96

M_CAP

Uncertain

0.14

MetaRNN

Pathogenic

0.82

MetaSVM

Uncertain

0.20

MutationAssessor

Benign

1.9

PhyloP100

7.9

PrimateAI

Uncertain

0.75

PROVEAN

Benign

-0.55

REVEL

Pathogenic

0.66

Sift

Uncertain

0.0030

Sift4G

Pathogenic

0.0010

Polyphen

0.99

Vest4

0.82

MutPred

0.71

Loss of disorder (P = 0.1357)

MVP

0.86

MPC

0.97

ClinPred

0.97

GERP RS

6.0

Varity_R

0.65

gMVP

0.76

Mutation Taster

=49/51

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over