rs189442556

chr2-174753558-G-A

Variant summary

Our verdict is Benign. Variant got -14 ACMG points: 0P and 14B. BP4_Moderate BP6_Very_Strong BS1

The NM_000079.4(CHRNA1):c.723C>T(p.Pro241=) variant causes a synonymous change. The variant allele was found at a frequency of 0.000593 in 1,614,200 control chromosomes in the GnomAD database, including 9 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.00041 (1 hom., cov: 31)
  • Exomes 𝑓: 0.00061 (8 hom.)
• Consequence: CHRNA1 NM_000079.4 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:4
• Conservation: PhyloP100: 3.60

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]

(HGNC:):

ACMG classification

Verdict is Benign. Variant got -14 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.46).
• BP6: Variant 2-174753558-G-A is Benign according to our data. Variant chr2-174753558-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 493302.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population sas. gnomad4 allele frequency = 0.000407 (62/152306) while in subpopulation SAS AF= 0.0102 (49/4826). AF 95% confidence interval is 0.00789. There are 1 homozygotes in gnomad4. There are 48 alleles in male gnomad4 subpopulation. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHRNA1	NM_000079.4	c.723C>T	p.Pro241=	synonymous_variant	6/9	ENST00000348749.9
CHRNA1	NM_001039523.3	c.798C>T	p.Pro266=	synonymous_variant	7/10
CHRNA1	XM_017003256.2	c.819C>T	p.Pro273=	synonymous_variant	6/9
CHRNA1	XM_017003257.2	c.744C>T	p.Pro248=	synonymous_variant	5/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNA1	ENST00000348749.9	c.723C>T	p.Pro241=	synonymous_variant	6/9	1	NM_000079.4	P1
	ENST00000442996.1	n.322-19191G>A		intron_variant, non_coding_transcript_variant		1

Frequencies

GnomAD3 genomes AF: 0.000407 AC: 62 AN: 152188 Hom.: 1 Cov.: 31

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000192

Gnomad SAS AF: 0.0101

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000162

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00115 AC: 288 AN: 251358 Hom.: 1 AF XY: 0.00160 AC XY: 217 AN XY: 135844

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 SAS exome AF: 0.00892

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000123

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.000612 AC: 895 AN: 1461894 Hom.: 8 Cov.: 31 AF XY: 0.000903 AC XY: 657 AN XY: 727248

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.0000447

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00881

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000728

Gnomad4 OTH exome AF: 0.000629

GnomAD4 genome AF: 0.000407 AC: 62 AN: 152306 Hom.: 1 Cov.: 31 AF XY: 0.000645 AC XY: 48 AN XY: 74476

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000193

Gnomad4 SAS AF: 0.0102

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000162

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000245 Hom.: 0

Bravo AF: 0.0000831

Asia WGS AF: 0.00231 AC: 8 AN: 3478

EpiCase AF: 0.000436

EpiControl AF: 0.000178

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Lethal multiple pterygium syndrome Benign:2

Benign, criteria provided, single submitter	clinical testing	Invitae	Jan 30, 2024	- -
Likely benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

not provided Benign:1

Likely benign, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Oct 01, 2023

CHRNA1: PM2:Supporting, BP4, BP7 -

Congenital myasthenic syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.46
Cadd	Benign	10
Dann	Benign	0.86

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

Publications

LitVar

Other links and lift over

dbSNP: rs189442556; hg19: chr2-175618286;