chr2-174750025-G-A

Variant names:

• chr2-174750025-G-A
• rs1553469062
• NM_000079.4:c.923C>T

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_001039523.3(CHRNA1):​c.998C>T​(p.Ser333Phe) 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 Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. S333S) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CHRNA1 NM_001039523.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.04
• Publications: 0 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), PanelApp Australia
• lethal multiple pterygium syndrome

  Inheritance: AR Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P
• myasthenic syndrome, congenital, 1B, fast-channel

  Inheritance: AR, AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, PanelApp Australia
• postsynaptic congenital myasthenic syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000236449 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 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, 9 uncertain in NM_001039523.3
• 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: 1.6453 (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, 0.943

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001039523.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNA1	NM_000079.4	MANE Select	c.923C>T	p.Ser308Phe	missense	Exon 7 of 9	NP_000070.1
	CHRNA1	NM_001039523.3		c.998C>T	p.Ser333Phe	missense	Exon 8 of 10	NP_001034612.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNA1	ENST00000348749.9	TSL:1 MANE Select	c.923C>T	p.Ser308Phe	missense	Exon 7 of 9	ENSP00000261008.5
	ENSG00000236449	ENST00000442996.1	TSL:1	n.321+20201G>A		intron	N/A
	CHRNA1	ENST00000261007.9	TSL:2	c.998C>T	p.Ser333Phe	missense	Exon 8 of 10	ENSP00000261007.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Lethal multiple pterygium syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.90	D
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.56	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Pathogenic	3.3	M
PhyloP100		8.0
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-5.8	D
REVEL	Pathogenic	0.91
Sift	Uncertain	0.0040	D
Sift4G	Uncertain	0.012	D
Polyphen		1.0	D
Vest4		0.94
MutPred		0.77		Loss of glycosylation at S333 (P = 0.0539)
MVP		0.95
MPC		0.95
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.95
gMVP		0.99
Mutation Taster		=7/93	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

Other links and lift over

dbSNP: rs1553469062; hg19: chr2-175614753;