NM_000079.4:c.805G>T

Variant names:

• chr2-174750143-C-A
• rs137852803
• NM_000079.4:c.805G>T

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1 PM2 PP2 PP3_Strong PP5

The NM_000079.4(CHRNA1):​c.805G>T​(p.Val269Phe) 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. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V269L) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 31)
• Consequence: CHRNA1 NM_000079.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:1
• Conservation: PhyloP100: 7.91
• Publications: 5 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: Pathogenic. The variant received 10 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000079.4
• 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, 0.961
• PP5: Variant 2-174750143-C-A is Pathogenic according to our data. Variant chr2-174750143-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 18381.

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.805G>T	p.Val269Phe	missense	Exon 7 of 9	NP_000070.1	Q53SH4
	CHRNA1	NM_001039523.3		c.880G>T	p.Val294Phe	missense	Exon 8 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.805G>T	p.Val269Phe	missense	Exon 7 of 9	ENSP00000261008.5	P02708-2
	ENSG00000236449	ENST00000442996.1	TSL:1	n.321+20319C>A		intron	N/A
	CHRNA1	ENST00000261007.9	TSL:2	c.880G>T	p.Val294Phe	missense	Exon 8 of 10	ENSP00000261007.5	P02708-1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 31

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
1	-	-	Congenital myasthenic syndrome 1A (1)
1	-	-	Inborn genetic diseases (1)
-	1	-	Lethal multiple pterygium syndrome (1)
1	-	-	Myasthenic syndrome, congenital, 1B, fast-channel (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.43
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.92	D
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.91
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Pathogenic	3.0	M
PhyloP100		7.9
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-4.6	D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.86		Loss of stability (P = 0.0579)
MVP		0.90
MPC		1.0
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.97
gMVP		0.97
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs137852803; hg19: chr2-175614871;