Genetic Variant CLCN1:p.Val88Val (chr7-143319838-G-C) – ACMG Classification: Likely_benign (-3 pts)

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2BP4_StrongBP7

The NM_000083.3(CLCN1):c.264G>C(p.Val88Val) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,580 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. V88V) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

CLCN1
NM_000083.3 synonymous

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.761

Publications

0 publications found

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 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

CLCN1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.5).

BP7

Synonymous conserved (PhyloP=0.761 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CLCN1	NM_000083.3 link	c.264G>C	p.Val88Val	synonymous_variant	Exon 2 of 23	ENST00000343257.7	NP_000074.3
CLCN1	NR_046453.2 link	n.366G>C		non_coding_transcript_exon_variant	Exon 2 of 22

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein
CLCN1	ENST00000343257.7 link	c.264G>C	p.Val88Val	synonymous_variant	Exon 2 of 23	1	NM_000083.3	ENSP00000339867.2
CLCN1	ENST00000432192.6 link	n.30G>C		non_coding_transcript_exon_variant	Exon 1 of 23	1		ENSP00000395949.2
CLCN1	ENST00000650516.2 link	c.264G>C	p.Val88Val	synonymous_variant	Exon 2 of 23			ENSP00000498052.2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1461580

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727118

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33468

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.00000270

AC:

AN:

1111750

Other (OTH)

AF:

0.00

AC:

AN:

60376

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.50

CADD

Benign

7.5

(source)

DANN

Benign

0.66

PhyloP100

0.76

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over