7-143331615-C-G

Variant names:

• chr7-143331615-C-G
• rs201714423
• NM_000083.3:c.1129C>G

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PP2 PP3_Moderate

The NM_000083.3(CLCN1):​c.1129C>G​(p.Arg377Gly) variant causes a missense change. The variant allele was found at a frequency of 0.00000547 in 1,461,770 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R377Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: CLCN1 NM_000083.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.76
• Publications: 0 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 3 ACMG points.

• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.931

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000083.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CLCN1	NM_000083.3	MANE Select	c.1129C>G	p.Arg377Gly	missense	Exon 10 of 23	NP_000074.3
	CLCN1	NR_046453.2		n.1234C>G		non_coding_transcript_exon	Exon 10 of 22

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CLCN1	ENST00000343257.7	TSL:1 MANE Select	c.1129C>G	p.Arg377Gly	missense	Exon 10 of 23	ENSP00000339867.2
	CLCN1	ENST00000432192.6	TSL:1	n.*414C>G		non_coding_transcript_exon	Exon 10 of 23	ENSP00000395949.2
	CLCN1	ENST00000432192.6	TSL:1	n.*414C>G		3_prime_UTR	Exon 10 of 23	ENSP00000395949.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461770 Hom.: 0 Cov.: 31 AF XY: 0.00000688 AC XY: 5 AN XY: 727190

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000719 AC: 8 AN: 1111920

Other (OTH) AF: 0.00 AC: 0 AN: 60388

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Aug 30, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1129C>G (p.R377G) alteration is located in exon 10 (coding exon 10) of the CLCN1 gene. This alteration results from a C to G substitution at nucleotide position 1129, causing the arginine (R) at amino acid position 377 to be replaced by a glycine (G). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

not provided Uncertain:1

Jan 27, 2023

Athena Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Available data are insufficient to determine the clinical significance of the variant at this time. This variant has not been reported in large, multi-ethnic general populations. (http://gnomad.broadinstitute.org) Computational tools predict that this variant is damaging.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.66
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.36
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	D
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Benign	0.84	T
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.93	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	M
PhyloP100		4.8
PrimateAI	Uncertain	0.49	T
PROVEAN	Pathogenic	-6.5	D
REVEL	Pathogenic	0.87
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.89
MutPred		0.67		Loss of MoRF binding (P = 0.0052)
MVP		0.99
MPC		0.84
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.92
gMVP		0.91
Mutation Taster		=20/80	disease causing

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: rs201714423; hg19: chr7-143028708;