2-174753626-G-T

Variant names:

• chr2-174753626-G-T
• rs150638770
• NM_000079.4:c.655C>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_000079.4(CHRNA1):​c.655C>A​(p.Leu219Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,894 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. L219L) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CHRNA1 NM_000079.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 8.09
• Publications: 2 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: Uncertain_significance. The variant received 3 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNA1	NM_000079.4	c.655C>A	p.Leu219Met	missense_variant	Exon 6 of 9	ENST00000348749.9	NP_000070.1
CHRNA1	NM_001039523.3	c.730C>A	p.Leu244Met	missense_variant	Exon 7 of 10		NP_001034612.1
CHRNA1	XM_017003256.2	c.751C>A	p.Leu251Met	missense_variant	Exon 6 of 9		XP_016858745.1
CHRNA1	XM_017003257.2	c.676C>A	p.Leu226Met	missense_variant	Exon 5 of 8		XP_016858746.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA1	ENST00000348749.9	c.655C>A	p.Leu219Met	missense_variant	Exon 6 of 9	1	NM_000079.4	ENSP00000261008.5

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251472 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461894 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727248

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.020
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Benign	0.32	.;T;T;T;T;.
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.96	D;D;D;D;D;D
M_CAP	Benign	0.055	D
MetaRNN	Uncertain	0.73	D;D;D;D;D;D
MetaSVM	Uncertain	0.090	D
MutationAssessor	Benign	1.9	.;L;.;.;.;.
PhyloP100		8.1
PrimateAI	Uncertain	0.73	T
PROVEAN	Benign	0.14	N;N;N;N;.;N
REVEL	Uncertain	0.47
Sift	Benign	0.092	T;T;T;T;.;T
Sift4G	Benign	0.23	T;T;T;T;.;T
Polyphen		1.0, 1.0	.;D;.;.;.;D
Vest4		0.59
MutPred		0.49		.;Loss of sheet (P = 0.0817);.;.;.;.;
MVP		0.64
MPC		0.89
ClinPred		0.80	D
GERP RS		5.2
Varity_R		0.64
gMVP		0.52
Mutation Taster		=19/81	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: rs150638770; hg19: chr2-175618354;