Genetic Variant NM_000747.3:c.720C>T (chr17-7448688-C-T) – ACMG Classification: Likely_benign (-4 pts)

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_ModerateBP6BP7

The NM_000747.3(CHRNB1):c.720C>T(p.Ile240Ile) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000284 in 1,614,102 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00021 ( 0 hom., cov: 31)

Exomes 𝑓: 0.00029 ( 0 hom. )

Consequence

CHRNB1
NM_000747.3 synonymous

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:2

Conservation

PhyloP100: 1.34

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

CHRNB1 links:

ENSG00000308645 (HGNC:):

ENSG00000308645 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -4 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.3).

BP6

Variant 17-7448688-C-T is Benign according to our data. Variant chr17-7448688-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 256775.

BP7

Synonymous conserved (PhyloP=1.34 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000747.3. 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
	CHRNB1	NM_000747.3	MANE Select	c.720C>T	p.Ile240Ile	synonymous	Exon 7 of 11	NP_000738.2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
CHRNB1	ENST00000306071.7	TSL:1 MANE Select	c.720C>T	p.Ile240Ile	synonymous	Exon 7 of 11	ENSP00000304290.2	P11230-1
CHRNB1	ENST00000536404.6	TSL:2	c.504C>T	p.Ile168Ile	synonymous	Exon 6 of 10	ENSP00000439209.2	P11230-2
CHRNB1	ENST00000576360.1	TSL:3	c.504C>T	p.Ile168Ile	synonymous	Exon 6 of 10	ENSP00000459092.1	I3L1T7

Frequencies

GnomAD3 genomes

AF:

0.000210

AC:

AN:

152212

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000456

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000994

AC:

AN:

251452

AF XY:

0.0000736

show subpopulations

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:

0.000193

Gnomad OTH exome

AF:

0.000326

GnomAD4 exome

AF:

0.000292

AC:

427

AN:

1461890

Hom.:

Cov.:

AF XY:

0.000279

AC XY:

203

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.0000383

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000344

AC:

383

AN:

1112008

Other (OTH)

AF:

0.000695

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

104

130

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

100

<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:

0.000210

AC:

AN:

152212

Hom.:

Cov.:

AF XY:

0.000161

AC XY:

AN XY:

74362

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41440

American (AMR)

AF:

0.00

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5202

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000456

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.486

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:

0.000181

Hom.:

Bravo

AF:

0.000208

EpiCase

AF:

0.000164

EpiControl

AF:

0.000178

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

Congenital myasthenic syndrome 2A (1)

Congenital myasthenic syndrome 4C (1)

not specified (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.30

CADD

Benign

(source)

DANN

Benign

0.82

PhyloP100

1.3

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.050

Details are displayed if max score is > 0.2

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

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over