17-7445132-C-T

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_000747.3(CHRNB1):c.5C>T(p.Thr2Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000373 in 1,608,516 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. T2T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

CHRNB1
NM_000747.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: -0.0400

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.11911431).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHRNB1	NM_000747.3 linkuse as main transcript	c.5C>T	p.Thr2Ile	missense_variant	1/11	ENST00000306071.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNB1	ENST00000306071.7 linkuse as main transcript	c.5C>T	p.Thr2Ile	missense_variant	1/11	1	NM_000747.3	P1	P11230-1
CHRNB1	ENST00000572857.5 linkuse as main transcript	c.5C>T	p.Thr2Ile	missense_variant	1/6	4
CHRNB1	ENST00000574054.1 linkuse as main transcript	n.25C>T		non_coding_transcript_exon_variant	1/2	2

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152234

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000385

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000128

AC:

AN:

233532

Hom.:

AF XY:

0.00000775

AC XY:

AN XY:

129114

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000169

Gnomad SAS 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:

0.00000275

AC:

AN:

1456164

Hom.:

Cov.:

AF XY:

0.00000276

AC XY:

AN XY:

724378

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000504

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000180

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152352

Hom.:

Cov.:

AF XY:

0.0000268

AC XY:

AN XY:

74498

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000386

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000756

ExAC

AF:

0.00000832

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Congenital myasthenic syndrome 2A

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Feb 03, 2022

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt CHRNB1 protein function. ClinVar contains an entry for this variant (Variation ID: 1051589). This variant has not been reported in the literature in individuals affected with CHRNB1-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 2 of the CHRNB1 protein (p.Thr2Ile). -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 20, 2023

The c.5C>T (p.T2I) alteration is located in exon 1 (coding exon 1) of the CHRNB1 gene. This alteration results from a C to T substitution at nucleotide position 5, causing the threonine (T) at amino acid position 2 to be replaced by an isoleucine (I). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Benign

-0.073

BayesDel_noAF

Benign

-0.34

Cadd

Benign

Dann

Uncertain

0.99

DEOGEN2

Benign

0.059

T;.

Eigen

Benign

-0.69

Eigen_PC

Benign

-0.59

FATHMM_MKL

Benign

0.24

M_CAP

Benign

0.031

MetaRNN

Benign

0.12

T;T

MetaSVM

Benign

-0.87

MutationAssessor

Benign

1.1

L;.

MutationTaster

Benign

1.0

N;D

PrimateAI

Uncertain

0.69

PROVEAN

Benign

-1.1

N;.

REVEL

Benign

0.18

Sift

Uncertain

0.014

D;.

Sift4G

Uncertain

0.033

D;D

Polyphen

0.0

B;.

Vest4

0.23

MutPred

0.29

Loss of glycosylation at T2 (P = 0.0122);Loss of glycosylation at T2 (P = 0.0122);

MVP

0.85

MPC

0.43

ClinPred

0.12

GERP RS

2.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

Varity_R

0.052

gMVP

0.30

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over