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Congenital myotonia, autosomal dominant form

CLCN1 · rs1266327660

Stands on its own. Nothing else here links to this position yet — but the page above is the point: what the research found, what each genotype means, and where it came from, in language you can read. Links to conditions, drugs and the senses appear automatically if we write them.

Strength of the evidence

2 / 4

ClinVar classifies it as disease-causing (or likely), reviewed at 1 of 4 stars.

How this is scored

4: ClinVar disease-causing, reviewed by an expert panel or a guideline (3–4 stars). 3: ClinVar, several labs agreeing (2 stars), or a genetic study at p ≤ 10⁻⁵⁰. 2: ClinVar from one lab (1 star), or p ≤ 10⁻²⁰. 1: ClinVar submitted without criteria (0 stars), or genome-wide significance (p ≤ 5×10⁻⁸). The higher of the two counts. It says how solid the evidence is, not whether it matters for a particular person.

What ClinVar records

Classification Pathogenic for Congenital myotonia, autosomal dominant form, Congenital myotonia, autosomal recessive form; criteria provided, single submitter (1 of 4 stars, 1 submitter), last evaluated 2024-05-20. ClinVar record 835784 NM_000083.3(CLCN1):c.860T>A (p.Leu287Gln)

Classification Likely pathogenic for Congenital myotonia, autosomal dominant form; criteria provided, single submitter (1 of 4 stars, 1 submitter), last evaluated 2024-03-26. ClinVar record 3065364 NM_000083.3(CLCN1):c.860T>C (p.Leu287Pro)

Classification Uncertain significance for Inborn genetic diseases; criteria provided, single submitter (1 of 4 stars, 1 submitter), last evaluated 2021-09-17. ClinVar record 2251048 NM_000083.3(CLCN1):c.860T>G (p.Leu287Arg)

Change history MyGeneLog™ keeps a copy of every weekly release from 2026-10-19 and compares them. This position's classification has not changed since.

What this is ClinVar's aggregate record for this position (as of its 2026-10-19 release), not a result about you. A classification describes the variant against the condition named, as laboratories submitted it. Whether a person carries this variant, and what that would mean for them, is a question for a clinical test and a genetic counsellor.

What each result means

A/A Two copies of the version ClinVar lists as disease-causing for Congenital myotonia, autosomal dominant form. A result like this should be confirmed by a medical genetic test and talked through with a doctor; consumer DNA files can misread rare variants. So far only one lab has made this call, so it may change. (ClinVar VCV000835784, criteria provided, single submitter)

A/T One copy of the version ClinVar lists as disease-causing for Congenital myotonia, autosomal dominant form. Some conditions need only one copy; for others, one copy makes a person a carrier who is usually healthy but can pass it on. A genetic counsellor can say which applies. So far only one lab has made this call, so it may change. (ClinVar VCV000835784, criteria provided, single submitter)

T/T No copy of the version ClinVar lists as disease-causing for Congenital myotonia, autosomal dominant form. This is the usual result. So far only one lab has made this call, so it may change. (ClinVar VCV000835784, criteria provided, single submitter)

Source: ClinVar VCV000835784, criteria provided, single submitter

Quoting this page

Licensed CC BY-NC 4.0: free to read, share and adapt for non-commercial use, naming MyGeneLog™ and linking the exact page. Commercial use, including training or serving a commercial AI system, needs a licence — https://www.mygenelog.com/license

Congenital myotonia, autosomal dominant form (rs1266327660). MyGeneLog™. https://www.mygenelog.com/variants/rs1266327660

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