rs747078264

Variant names:

• chr7-143321816-G-A
• rs747078264
• NM_000083.3:c.664G>A

Your query was ambiguous. Multiple possible variants found:

• chr7-143321816-G-A
• chr7-143321816-G-T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 3P and 2B. PM1 PP2 BP4_Moderate

The NM_000083.3(CLCN1):​c.664G>A​(p.Gly222Ser) variant causes a missense change. The variant allele was found at a frequency of 0.0000465 in 1,614,112 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 0.000046 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000047 (0 hom.)
• Consequence: CLCN1 NM_000083.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.79
• Publications: 3 publications found

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 Gene-Disease associations (from GenCC):

• myotonia congenita, autosomal dominant

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• myotonia congenita, autosomal recessive

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• Thomsen and Becker disease

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_000083.3
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 106 curated pathogenic missense variants (we use a threshold of 10). The gene has 18 curated benign missense variants. Gene score misZ: 0.21191 (below the threshold of 3.09). Trascript score misZ: 0.95247 (below the threshold of 3.09). GenCC associations: The gene is linked to myotonia congenita, autosomal dominant, myotonia congenita, autosomal recessive, Thomsen and Becker disease.
• BP4: Computational evidence support a benign effect (MetaRNN=0.20835549).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CLCN1	NM_000083.3	c.664G>A	p.Gly222Ser	missense_variant	Exon 5 of 23	ENST00000343257.7	NP_000074.3
CLCN1	NR_046453.2	n.766G>A		non_coding_transcript_exon_variant	Exon 5 of 22

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CLCN1	ENST00000343257.7	c.664G>A	p.Gly222Ser	missense_variant	Exon 5 of 23	1	NM_000083.3	ENSP00000339867.2

Frequencies

GnomAD3 genomes AF: 0.0000460 AC: 7 AN: 152230 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00144

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000796 AC: 20 AN: 251352 AF XY: 0.0000662

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00129

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.000489

GnomAD4 exome AF: 0.0000465 AC: 68 AN: 1461882 Hom.: 0 Cov.: 33 AF XY: 0.0000440 AC XY: 32 AN XY: 727240

African (AFR) AF: 0.0000597 AC: 2 AN: 33480

American (AMR) AF: 0.0000224 AC: 1 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00115 AC: 30 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.000867 AC: 5 AN: 5768

European-Non Finnish (NFE) AF: 0.0000198 AC: 22 AN: 1112004

Other (OTH) AF: 0.000116 AC: 7 AN: 60396

GnomAD4 genome AF: 0.0000460 AC: 7 AN: 152230 Hom.: 0 Cov.: 33 AF XY: 0.0000538 AC XY: 4 AN XY: 74372

African (AFR) AF: 0.00 AC: 0 AN: 41454

American (AMR) AF: 0.00 AC: 0 AN: 15288

Ashkenazi Jewish (ASJ) AF: 0.00144 AC: 5 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68050

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.000120 Hom.: 0

Bravo AF: 0.0000680

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Jul 05, 2017

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Apr 08, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 222 of the CLCN1 protein (p.Gly222Ser). This variant is present in population databases (rs747078264, gnomAD 0.1%). This missense change has been observed in individual(s) with autosomal recessive myotonia congenita (PMID: 23810313). ClinVar contains an entry for this variant (Variation ID: 521921). 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. Experimental studies have shown that this missense change does not substantially affect CLCN1 function (PMID: 34529042). 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	0.15
BayesDel_addAF	Uncertain	0.12	D
BayesDel_noAF	Uncertain	0.050
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.35	.;T
Eigen	Uncertain	0.28
Eigen_PC	Uncertain	0.36
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Uncertain	0.086	D
MetaRNN	Benign	0.21	T;T
MetaSVM	Uncertain	0.32	D
MutationAssessor	Benign	-0.99	.;N
PhyloP100		6.8
PrimateAI	Uncertain	0.73	T
PROVEAN	Benign	-0.67	.;N
REVEL	Uncertain	0.63
Sift	Benign	0.36	.;T
Sift4G	Benign	0.62	.;T
Polyphen		0.97	.;D
Vest4		0.52
MVP		0.95
MPC		0.62
ClinPred		0.31	T
GERP RS		5.0
Varity_R		0.38
gMVP		0.70
Mutation Taster		=61/39	polymorphism

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

Other links and lift over

dbSNP: rs747078264; hg19: chr7-143018909;