Sensitive

Long QT syndrome 1

KCNQ1 · rs120074185

Strength of the evidence

3 / 4

ClinVar classifies it as disease-causing (or likely), reviewed at 2 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 Long QT syndrome 1, Congenital long QT syndrome, Long QT syndrome, Cardiovascular phenotype, Cardiac arrhythmia and 1 more; criteria provided, multiple submitters, no conflicts (2 of 4 stars, 15 submitters), last evaluated 2026-01-16. ClinVar record 3126 NM_000218.3(KCNQ1):c.1663C>T (p.Arg555Cys)

Classification Pathogenic/Likely pathogenic for Congenital long QT syndrome, Long QT syndrome, Cardiac arrhythmia, KCNQ1-related disorder, Long QT syndrome 1; criteria provided, multiple submitters, no conflicts (2 of 4 stars, 8 submitters), last evaluated 2025-11-16. ClinVar record 67046 NM_000218.3(KCNQ1):c.1663C>A (p.Arg555Ser)

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

C/C No copy of the version ClinVar lists as disease-causing for Long QT syndrome 1. This is the usual result. (ClinVar VCV000003126, criteria provided, multiple submitters, no conflicts)
C/T One copy of the version ClinVar lists as disease-causing for Long QT syndrome 1. 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. (ClinVar VCV000003126, criteria provided, multiple submitters, no conflicts)
T/T Two copies of the version ClinVar lists as disease-causing for Long QT syndrome 1. 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. (ClinVar VCV000003126, criteria provided, multiple submitters, no conflicts)

Source: ClinVar VCV000003126, criteria provided, multiple submitters, no conflicts

Questions about rs120074185

What is rs120074185?

rs120074185 is a single position in the genome, in or near the KCNQ1 gene. Published research associates it with long qt syndrome 1. A single variant does not decide an outcome — it shifts a probability, and for most common variants the shift is small.

Does having rs120074185 mean I will get this?

No. Common variants like this one move a probability slightly and, on their own, rarely decide anything about one person. Nothing on this page is a diagnosis, and health decisions should be made with a clinician who can see your whole picture.

Where does the information about rs120074185 come from?

ClinVar VCV000003126, criteria provided, multiple submitters, no conflicts. Every variant on MyGeneLog comes from public primary sources and is published with its citation and the date it was checked.

Quoting this page

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Long QT syndrome 1 (rs120074185). MyGeneLog™. https://www.mygenelog.com/variants/rs120074185

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