chr7-143316255-T-C

Variant names:

• chr7-143316255-T-C
• rs1194717455
• NM_000083.3:c.43T>C

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 0P and 1B. BP4

The NM_000083.3(CLCN1):​c.43T>C​(p.Trp15Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,613,620 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 Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000062 (0 hom.)
• Consequence: CLCN1 NM_000083.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.19

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]

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.34406257).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CLCN1	NM_000083.3	c.43T>C	p.Trp15Arg	missense_variant	Exon 1 of 23	ENST00000343257.7	NP_000074.3
CLCN1	NR_046453.2	n.145T>C		non_coding_transcript_exon_variant	Exon 1 of 22

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CLCN1	ENST00000343257.7	c.43T>C	p.Trp15Arg	missense_variant	Exon 1 of 23	1	NM_000083.3	ENSP00000339867.2
CLCN1	ENST00000650516.2	c.43T>C	p.Trp15Arg	missense_variant	Exon 1 of 23			ENSP00000498052.2

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152052 Hom.: 0 Cov.: 32

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 250968 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135672

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

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: 0.00000616 AC: 9 AN: 1461568 Hom.: 0 Cov.: 32 AF XY: 0.00000825 AC XY: 6 AN XY: 727102

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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: 0.00000720

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152052 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74284

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: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital myotonia, autosomal recessive form;C2936781:Congenital myotonia, autosomal dominant form Uncertain:1

Aug 24, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals affected with CLCN1-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.003%). This sequence change replaces tryptophan, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 15 of the CLCN1 protein (p.Trp15Arg). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on 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	Benign	0.33
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	0.030
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.11	.;T
Eigen	Uncertain	0.34
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Benign	0.62	T;T
M_CAP	Uncertain	0.15	D
MetaRNN	Benign	0.34	T;T
MetaSVM	Uncertain	0.28	D
MutationAssessor	Benign	0.90	.;L
PrimateAI	Uncertain	0.58	T
PROVEAN	Benign	-1.2	.;N
REVEL	Uncertain	0.56
Sift	Uncertain	0.0030	.;D
Sift4G	Uncertain	0.032	.;D
Polyphen		0.84	.;P
Vest4		0.62
MutPred		0.29		Gain of MoRF binding (P = 0.0532);Gain of MoRF binding (P = 0.0532);
MVP		0.96
MPC		1.0
ClinPred		0.88	D
GERP RS		5.2
Varity_R		0.43
gMVP		0.45

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

Other links and lift over

dbSNP: rs1194717455; hg19: chr7-143013348;