CACNA1C

The goal of this clinical trial is to learn if an antisense oligonucleotide (TS1-ASO) can safely treat and potentially prevent neuropsychiatric and neurodevelopmental symptoms in pediatric participants (age \>2 months) with Timothy Syndrome Type 1 (TS1). The main questions it aims to answer are: 1. Is TS1-ASO safe and well tolerated when administered intrathecally in children with TS1? 2. What are the pharmacokinetics and preliminary efficacy of TS1-ASO on neurodevelopmental and neurologic outcomes? This is a single-arm study (no comparison group). Participants will: 1. Receive intrathecal injections of TS1-ASO via lumbar puncture using a stepwise dose-escalation approach 2. Undergo safety monitoring including neurologic exams, cardiac monitoring, laboratory testing, and adverse event assessments 3. Provide cerebrospinal fluid (CSF) and blood samples for pharmacokinetic and biomarker analyses 4. Complete neurodevelopmental, behavioral, and functional assessments (e.g., adaptive behavior, motor function, communication, seizure tracking) over time

Simons Searchlight is an observational, online, international research program for families with rare genetic variants that cause neurodevelopmental disorders and may be associated with autism. Simons Searchlight collects medical, behavioral, learning, and developmental information from people who have these rare genetic changes. The goal of this study is to improve the clinical care and treatment for these people. Simons Searchlight partners with families to collect data and distribute it to qualified researchers.