17-7448695-C-T

Position:

chr17-7448695-C-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PP3_StrongPP5_Very_Strong

The NM_000747.3(CHRNB1):c.727C>T(p.Arg243Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000018 in 1,614,214 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000017 ( 0 hom. )

Consequence

CHRNB1
NM_000747.3 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3

Conservation

PhyloP100: 2.05

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:

CHRNB1 (HGNC:):

CHRNB1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.985

PP5

Variant 17-7448695-C-T is Pathogenic according to our data. Variant chr17-7448695-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 448999.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-7448695-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CHRNB1	NM_000747.3 linkuse as main transcript	c.727C>T	p.Arg243Cys	missense_variant	7/11	ENST00000306071.7	NP_000738.2	P11230-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHRNB1	ENST00000306071.7 linkuse as main transcript	c.727C>T	p.Arg243Cys	missense_variant	7/11	1	NM_000747.3	ENSP00000304290.2		P11230-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152206

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:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000239

AC:

AN:

251474

Hom.:

AF XY:

0.0000294

AC XY:

AN XY:

135916

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000440

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000171

AC:

AN:

1461890

Hom.:

Cov.:

AF XY:

0.0000165

AC XY:

AN XY:

727246

show subpopulations

Gnomad4 AFR exome

AF:

0.0000597

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000180

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152324

Hom.:

Cov.:

AF XY:

0.0000268

AC XY:

AN XY:

74490

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000550

Hom.:

Bravo

AF:

0.0000189

ExAC

AF:

0.0000330

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Feb 07, 2024	Reported previously in an abstract using alternate nomenclature (R220C) in an individual with early-onset congenital myasthenia syndrome who also harbored a second variant in the CHRNB1 gene, but it is not known whether the variants occurred on the same (in cis) or on different (in trans) chromosomes (Muller JS et al. (2006) Neuromuscular Disorders. 16 (9-10):661 https://www.nmd-journal.com/article/S0960-8966(06)00226-4/fulltext); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 17686188, 34426522, 30290857, Mller2006) -
Likely pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Jun 01, 2022	CHRNB1: PM3:Strong, PM2 -

Congenital myasthenic syndrome 2A

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 10, 2024

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 243 of the CHRNB1 protein (p.Arg243Cys). This variant is present in population databases (rs199875082, gnomAD 0.003%). This missense change has been observed in individuals with autosomal recessive congenital myasthenic syndrome (PMID: 17686188; Invitae). It has also been observed to segregate with disease in related individuals. This variant is also known as R220C. ClinVar contains an entry for this variant (Variation ID: 448999). 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 expected to disrupt CHRNB1 protein function with a positive predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.98

BayesDel_addAF

Pathogenic

0.46

BayesDel_noAF

Pathogenic

0.51

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.89

D;.;.

Eigen

Uncertain

0.59

Eigen_PC

Uncertain

0.45

FATHMM_MKL

Uncertain

0.92

M_CAP

Uncertain

0.27

MetaRNN

Pathogenic

0.99

D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.8

H;.;.

PrimateAI

Uncertain

0.60

PROVEAN

Pathogenic

-7.4

D;D;.

REVEL

Pathogenic

0.94

Sift

Pathogenic

0.0

D;D;.

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0

D;.;.

Vest4

0.98

MVP

0.96

MPC

1.5

ClinPred

1.0

GERP RS

1.7

Varity_R

0.90

gMVP

0.96

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