2-174754376-A-G

Variant names:

• chr2-174754376-A-G
• rs1553469444
• NM_000079.4:c.383T>C

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_001039523.3(CHRNA1):​c.458T>C​(p.Val153Ala) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,870 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign 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. V153G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CHRNA1 NM_001039523.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 4.58
• 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: Uncertain_significance. The variant received 2 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: 1.6453 (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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.41033426).

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.383T>C	p.Val128Ala	missense	Exon 5 of 9	NP_000070.1
	CHRNA1	NM_001039523.3		c.458T>C	p.Val153Ala	missense	Exon 6 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.383T>C	p.Val128Ala	missense	Exon 5 of 9	ENSP00000261008.5
	CHRNA1	ENST00000409323.1	TSL:1	c.383T>C	p.Val128Ala	missense	Exon 5 of 6	ENSP00000386684.1
	ENSG00000236449	ENST00000442996.1	TSL:1	n.322-18373A>G		intron	N/A

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461870 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727232

African (AFR) AF: 0.00 AC: 0 AN: 33476

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: 0.0000116 AC: 1 AN: 86252

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5756

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.39
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.040
CADD	Benign	22
DANN	Benign	0.87
DEOGEN2	Benign	0.28	T
Eigen	Benign	-0.11
Eigen_PC	Benign	0.11
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.68	T
M_CAP	Benign	0.030	D
MetaRNN	Benign	0.41	T
MetaSVM	Benign	-0.58	T
MutationAssessor	Benign	0.80	N
PhyloP100		4.6
PrimateAI	Uncertain	0.73	T
PROVEAN	Benign	2.1	N
REVEL	Uncertain	0.41
Sift	Benign	1.0	T
Sift4G	Benign	1.0	T
Polyphen		0.053	B
Vest4		0.42
MutPred		0.76		Loss of sheet (P = 0.0817)
MVP		0.70
MPC		0.32
ClinPred		0.55	D
GERP RS		5.8
Varity_R		0.49
gMVP		0.74
Mutation Taster		=24/76	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: rs1553469444; hg19: chr2-175619104;