A conceptual model depicting the signs, symptoms, and impacts of Angelman syndrome (AS) based on existing literature and interviews with clinicians and caregivers provides a framework from which to select, adapt, or develop an appropriate clinical outcomes assessment (COA) tool for AS.

While, no single existing COA addresses all symptoms and experiences of individuals with AS, there are some outcomes assessments that include items relevant to elicited concepts in AS; adaptation of these instruments for use in the AS population should be explored.

The development of a COA that is fit-for-purpose for individuals with AS is important in being able to appropriately assess symptoms and experiences of such individuals in order to capture treatment benefit in drug development programs.