A Natural History Study of Participants With Potassium Sodium-Activated Channel Subfamily T Member 1 (KCNT1)-Related Epilepsy

Key Inclusion Criteria:

   - Must have clinically and genetically confirmed diagnosis of KCNT1-related epilepsy
   provided by the investigator. For purposes of this study, mutations that are
   genetically confirmed to cause KCNT1-related epilepsy are defined to specifically
   exclude known benign variants (e.g., distal C terminus, splice site, etc.).

   - Willingness of the participant and/or the participant's legally authorized
   representative (LAR) to comply with scheduled visits and study procedures.

Key Exclusion Criteria:

   - Any condition that may interfere with the assessment of KCNT1-related epilepsy and
   that is clearly not related to this disease (in the judgment of the investigator).

   - History of human immunodeficiency virus infection.

   - History of central nervous system (CNS) tumors or malignancies, including CNS
   metastatic disease.

   - Current enrollment or past enrollment in an interventional clinical study in which an
   investigational gene therapy is/was administered.

   - Enrollment in an interventional clinical study in which an investigational small
   molecule, antibody or antisense oligonucleotide (ASO) treatment or approved small
   molecule, antibody or ASO therapy for investigational use is administered within 1
   month (or 5 half-lives of study agent, whichever is longer) prior to the screening
   visit.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.