rs781689096

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PP5_Very_Strong

The NM_000747.3(CHRNB1):c.1218-9_1218-7delCTC variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000223 in 1,613,606 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000040 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

CHRNB1
NM_000747.3 splice_region, intron

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2

Conservation

PhyloP100: 1.13

Publications

0 publications found

Variant links:

Genes affected

CHRNB1 (HGNC:1961): (cholinergic receptor nicotinic beta 1 subunit) The muscle acetylcholine receptor is composed of five subunits: two alpha subunits and one beta, one gamma, and one delta subunit. This gene encodes the beta subunit of the acetylcholine receptor. The acetylcholine receptor changes conformation upon acetylcholine binding leading to the opening of an ion-conducting channel across the plasma membrane. Mutations in this gene are associated with slow-channel congenital myasthenic syndrome. [provided by RefSeq, Jul 2008]

CHRNB1 Gene-Disease associations (from GenCC):

congenital myasthenic syndrome 2C
Inheritance: AD, AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae), Ambry Genetics, Genomics England PanelApp
congenital myasthenic syndrome 1A
Inheritance: AD Classification: STRONG Submitted by: PanelApp Australia
congenital myasthenic syndrome 2A
Inheritance: AD Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Ambry Genetics
postsynaptic congenital myasthenic syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

CHRNB1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

PP5

Variant 17-7455781-ACTC-A is Pathogenic according to our data. Variant chr17-7455781-ACTC-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 504421.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNB1	NM_000747.3 link	c.1218-9_1218-7delCTC		splice_region_variant, intron_variant	Intron 9 of 10	ENST00000306071.7	NP_000738.2	P11230-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNB1	ENST00000306071.7 link	c.1218-9_1218-7delCTC		splice_region_variant, intron_variant	Intron 9 of 10	1	NM_000747.3	ENSP00000304290.2		P11230-1

Frequencies

GnomAD3 genomes

AF:

0.0000395

AC:

AN:

151730

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00115

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.000480

GnomAD2 exomes

AF:

0.0000438

AC:

AN:

251248

AF XY:

0.0000368

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.000893

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000881

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000205

AC:

AN:

1461876

Hom.:

AF XY:

0.0000151

AC XY:

AN XY:

727238

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.000574

AC:

AN:

26134

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000809

AC:

AN:

1112004

Other (OTH)

AF:

0.0000662

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.467

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000395

AC:

AN:

151730

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74092

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41306

American (AMR)

AF:

0.00

AC:

AN:

15204

Ashkenazi Jewish (ASJ)

AF:

0.00115

AC:

AN:

3464

East Asian (EAS)

AF:

0.00

AC:

AN:

5176

South Asian (SAS)

AF:

0.00

AC:

AN:

4796

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10548

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

67926

Other (OTH)

AF:

0.000480

AC:

AN:

2084

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000130

Hom.:

Bravo

AF:

0.0000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Congenital myasthenic syndrome 2A

Pathogenic:1

Jan 15, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change falls in intron 9 of the CHRNB1 gene. It does not directly change the encoded amino acid sequence of the CHRNB1 protein. This variant is present in population databases (rs781689096, gnomAD 0.09%). This variant has been observed in individual(s) with clinical features of autosomal recessive congenital myasthenic syndrome (PMID: 33296147; internal data). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

not provided

Pathogenic:1

Sep 18, 2018

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.1218-9_1218-7delCTC variant in the CHRNB1 gene has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. This variant reduces the quality of the natural splice acceptor site in intron 9, and is expected to cause abnormal gene splicing. The c.1218-9_1218-7delCTC variant is not observed at a significant frequency in large population cohorts (Lek et al., 2016). We interpret c.1218-9_1218-7delCTC as a likely pathogenic variant. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

1.1

La Branchor

0.27

BranchPoint Hunter

1.0

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.34

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.25

Position offset: -2

DS_AL_spliceai

0.34

Position offset: 13

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over