chr7-143321747-C-T

Position:

chr7-143321747-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1PP3_Strong

The NM_000083.3(CLCN1):c.595C>T(p.Arg199Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000663 in 1,614,082 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 Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000066 ( 0 hom. )

Consequence

CLCN1
NM_000083.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.83

Variant links:

Genes affected

CLCN1 (HGNC:2019): (chloride voltage-gated channel 1) The CLCN family of voltage-dependent chloride channel genes comprises nine members (CLCN1-7, Ka and Kb) which demonstrate quite diverse functional characteristics while sharing significant sequence homology. The protein encoded by this gene regulates the electric excitability of the skeletal muscle membrane. Mutations in this gene cause two forms of inherited human muscle disorders: recessive generalized myotonia congenita (Becker) and dominant myotonia (Thomsen). Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2012]

CLCN1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM1

In a topological_domain Cytoplasmic (size 12) in uniprot entity CLCN1_HUMAN there are 7 pathogenic changes around while only 0 benign (100%) in NM_000083.3

PP3

MetaRNN computational evidence supports a deleterious effect, 0.944

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CLCN1	NM_000083.3 linkuse as main transcript	c.595C>T	p.Arg199Cys	missense_variant	5/23	ENST00000343257.7	NP_000074.3
CLCN1	NR_046453.2 linkuse as main transcript	n.697C>T		non_coding_transcript_exon_variant	5/22

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CLCN1	ENST00000343257.7 linkuse as main transcript	c.595C>T	p.Arg199Cys	missense_variant	5/23	1	NM_000083.3	ENSP00000339867	P4

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152240

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:

0.000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000398

AC:

AN:

251482

Hom.:

AF XY:

0.0000515

AC XY:

AN XY:

135916

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000615

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000657

AC:

AN:

1461842

Hom.:

Cov.:

AF XY:

0.0000701

AC XY:

AN XY:

727224

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000818

Gnomad4 OTH exome

AF:

0.0000662

GnomAD4 genome

AF:

0.0000723

AC:

AN:

152240

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74372

show subpopulations

Gnomad4 AFR

AF:

0.0000241

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:

0.000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000148

Hom.:

Bravo

AF:

0.0000793

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000233

AC:

ExAC

AF:

0.0000576

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Congenital myotonia, autosomal recessive form;C2936781:Congenital myotonia, autosomal dominant form

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 23, 2022

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 199 of the CLCN1 protein (p.Arg199Cys). This variant is present in population databases (rs143506735, gnomAD 0.009%). This variant has not been reported in the literature in individuals affected with CLCN1-related conditions. ClinVar contains an entry for this variant (Variation ID: 583185). 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 CLCN1 protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.73

BayesDel_addAF

Pathogenic

0.33

BayesDel_noAF

Pathogenic

0.42

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.93

.;D

Eigen

Uncertain

0.65

Eigen_PC

Uncertain

0.60

FATHMM_MKL

Uncertain

0.86

LIST_S2

Pathogenic

0.98

D;D

M_CAP

Pathogenic

0.51

MetaRNN

Pathogenic

0.94

D;D

MetaSVM

Pathogenic

0.92

MutationAssessor

Uncertain

2.8

.;M

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.77

PROVEAN

Pathogenic

-7.8

.;D

REVEL

Pathogenic

0.85

Sift

Pathogenic

0.0

.;D

Sift4G

Pathogenic

0.0

.;D

Polyphen

1.0

.;D

Vest4

0.94

MVP

0.97

MPC

0.85

ClinPred

0.96

GERP RS

5.0

Varity_R

0.89

gMVP

0.81

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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