<qa>  What is the main study for Group 1: ISIS 304801-CS6?This is a multi-center, open-label study for Group 1: ISIS 304801-CS6 index study roll-over FCS patients, Group 2: ISIS 304801-CS16 index study roll-over FCS patients, and Group 3: FCS patients who did not participate in the ISIS 304801-CS6 or ISIS 304801-CS16 index studies. All patients will receive volanesorsen 300 mg once per week for 52 weeks. Patients will have the option of continuing dosing for an additional 52 weeks until an expanded access program is approved and available in their country. 