2-174748184-G-C

Variant names:

• chr2-174748184-G-C
• rs137852808
• NM_000079.4:c.1314C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM2 PP2 PP3_Strong PP5

The NM_000079.4(CHRNA1):​c.1314C>G​(p.Cys438Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C438Y) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CHRNA1 NM_000079.4 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: -0.304
• Publications: 6 publications found

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

ENSG00000236449 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 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 myasthenic syndrome, congenital, 1B, fast-channel, congenital myasthenic syndrome 1A, lethal multiple pterygium syndrome, postsynaptic congenital myasthenic syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.966
• PP5: Variant 2-174748184-G-C is Pathogenic according to our data. Variant chr2-174748184-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 18387.Status of the report is no_assertion_criteria_provided, 0 stars.

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.1314C>G	p.Cys438Trp	missense	Exon 9 of 9	NP_000070.1	Q53SH4
	CHRNA1	NM_001039523.3		c.1389C>G	p.Cys463Trp	missense	Exon 10 of 10	NP_001034612.1	P02708-1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNA1	ENST00000348749.9	TSL:1 MANE Select	c.1314C>G	p.Cys438Trp	missense	Exon 9 of 9	ENSP00000261008.5	P02708-2
	ENSG00000236449	ENST00000442996.1	TSL:1	n.321+18360G>C		intron	N/A
	CHRNA1	ENST00000261007.9	TSL:2	c.1389C>G	p.Cys463Trp	missense	Exon 10 of 10	ENSP00000261007.5	P02708-1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
1	-	-	Congenital myasthenic syndrome 1A (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Benign	19
DANN	Benign	0.97
DEOGEN2	Pathogenic	0.90	D
Eigen	Benign	-0.059
Eigen_PC	Benign	-0.30
FATHMM_MKL	Benign	0.64	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.49	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Uncertain	0.72	D
MutationAssessor	Pathogenic	3.4	M
PhyloP100		-0.30
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-7.7	D
REVEL	Pathogenic	0.83
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.78
MutPred		0.84		Gain of catalytic residue at L461 (P = 0.0675)
MVP		0.84
MPC		1.1
ClinPred		1.0	D
GERP RS		-4.0
Varity_R		0.94
gMVP		0.94
Mutation Taster		=0/100	disease causing (ClinVar)

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: rs137852808; hg19: chr2-175612912;