Is KCNQ2 a rare disease?

KCNQ2 is rare, representing around 10% of patients with epileptic encephalopathy with onset in the first three months of life; however, the incidence of KCNQ2 is approximately 2.8/100,000 live births (or over 3,000 new cases annually worldwide), which is roughly half the number of births of Dravet Syndrome, the most …

What is long QT syndrome type 2?

Long QT syndrome type 2 (LQT2) LQT2 results from insufficient potassium ion activity in the heart. This deficiency prevents proper electrical function in the heart and leads to arrhythmia (abnormal heart rhythm). Emotional stress, surprise, and startling can cause arrhythmias in people with LQT2.

What is de novo disease?

A genetic alteration that is present for the first time in one family member as a result of a variant (or mutation) in a germ cell (egg or sperm) of one of the parents, or a variant that arises in the fertilized egg itself during early embryogenesis. Also called de novo variant, new mutation, and new variant.

What is the KCNQ2 gene?

What is KCNQ2? The KCNQ2 gene provides instructions for making potassium channels in the brain cells. These channels allow potassium to move outside of the cell, and if the channels are not working properly, brain cells are predisposed to generate excessive electrical signals that may lead to seizures.

What are KCNQ2/3 channels in the brain?

KCNQ2/3 channels are buried in the exterior surface membrane of brain cells. Nearly all brain signaling cells, or neurons, have KCNQ2/3 channels. When these channels open, potassium ions flow across the membrane. The main normal role of KCNQ2/3 ion flow is to act as a brake, delaying, slowing, and limiting the electrical signaling of these neurons.

Can mutations in the KCNQ2 gene cause early onset epilepsy?

This study demonstrated that Mutations in the KCNQ2 gene encoding the voltage-gated potassium channel subunit Kv7.2 cause early onset epileptic encephalopathy .

How do you test for KCNQ2 variants?

KCNQ2 variants can only be identified by genetic testing. Targeted testing of the KCNQ2 gene specifically is the most direct method of testing an individual when there is a high degree of confidence that a variant in the KCNQ2 gene is likely to be the underlying cause, but this form of testing is being undertaken less commonly over time.