2-174754215-C-A

Variant names:

• chr2-174754215-C-A
• rs112674580
• NM_000079.4:c.540+4G>T

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000079.4(CHRNA1):​c.540+4G>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,700 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CHRNA1 NM_000079.4 splice_region, intron
• Scores: Splicing: ADA: 0.0003919
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.0880
• 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)
• 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: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.37).

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.540+4G>T		splice_region intron	N/A	NP_000070.1	Q53SH4
	CHRNA1	NM_001039523.3		c.615+4G>T		splice_region intron	N/A	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.540+4G>T		splice_region intron	N/A	ENSP00000261008.5	P02708-2
	CHRNA1	ENST00000409323.1	TSL:1	c.540+4G>T		splice_region intron	N/A	ENSP00000386684.1	G5E9G9
	ENSG00000236449	ENST00000442996.1	TSL:1	n.322-18534C>A		intron	N/A

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251258 AF XY: 0.00

Gnomad AFR exome AF: 0.0000615

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460700 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726662

African (AFR) AF: 0.0000598 AC: 2 AN: 33450

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86206

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53388

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4984

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111848

Other (OTH) AF: 0.00 AC: 0 AN: 60276

GnomAD4 genome Cov.: 31

Alfa AF: 0.00 Hom.: 1

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.37
CADD	Benign	12
DANN	Benign	0.73
PhyloP100		0.088

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00039
dbscSNV1_RF	Benign	0.048
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: rs112674580; hg19: chr2-175618943;