rs1554435319

chr7-143324418-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000083.3(CLCN1):c.779C>T(p.Pro260Leu) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. P260P) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: CLCN1 NM_000083.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 6.14

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_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 1 uncertain in NM_000083.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.843

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CLCN1	NM_000083.3	c.779C>T	p.Pro260Leu	missense_variant	7/23	ENST00000343257.7
CLCN1	NR_046453.2	n.884C>T		non_coding_transcript_exon_variant	7/22

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CLCN1	ENST00000343257.7	c.779C>T	p.Pro260Leu	missense_variant	7/23	1	NM_000083.3	P4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Athena Diagnostics	Nov 19, 2019	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Sep 07, 2021	- -

Congenital myotonia, autosomal dominant form Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genomic Research Center, Shahid Beheshti University of Medical Sciences

Dec 18, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.20
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.040
Cadd	Pathogenic	27
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.81	D
Eigen	Uncertain	0.46
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.90	D
M_CAP	Uncertain	0.26	D
MetaRNN	Pathogenic	0.84	D
MetaSVM	Uncertain	0.74	D
MutationAssessor	Benign	1.0	L
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.73	T
PROVEAN	Pathogenic	-4.5	D
REVEL	Pathogenic	0.73
Sift	Uncertain	0.0070	D
Sift4G	Uncertain	0.014	D
Polyphen		0.67	P
Vest4		0.83
MutPred		0.48		Loss of helix (P = 0.1299);
MVP		0.98
MPC		0.40
ClinPred		0.97	D
GERP RS		4.8
Varity_R		0.42
gMVP		0.75

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1554435319; hg19: chr7-143021511;