Long QT Syndrome (LQTS)

General: May be the cause of death in misdiagnosed SIDS/SUDI cases, and affects approximately 1 in 5000 individuals. It is defined by a QT interval of >460 ms; about 60% are symptomatic, with syncope, seizures, &/or sudden death, while ~40% may be completely asymptomatic. There are six variants:

• LQT1 (KVLQT): (~25% of cases) Chromosome 11, affects potassium channel. Also associated with drownings.
• LQT2 (HERG): (20~25% of cases) Chromosome 7, affects potassium channel.
• LQT3 (SCN5A): (~5% of cases) Chromosome 3, affects sodium channel.
• LQT4:
• LQT5:
• LQT6:

Gross: Normal.

Microscopic:

Differential Diagnosis:

• Other channelopathy

Stains/investigations:

• Positive:
• Negative:
• Suggested, focused panel: Molecular/cytogenetic analysis for LQT & other channelopathies.

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Images:


Cases:

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