You will be asked to complete a survey, either online or via a posted paper copy (postage free of charge). The survey includes 12 questionnaires which will take about 60 minutes to complete – this can be done in one sitting or multiple sittings. You will be asked a variety of questions and through your answers we will learn more about behaviour, wellbeing, emotion, cognition, and health in children and adults with genetic syndromes, neurodevelopmental conditions, and intellectual disabilities. We will also gain insights into access to support, service use, and family wellbeing. After you complete the survey, you have the option to answer another 5-minute questionnaire about your child/person you care for. We may also send this questionnaire to another caregiver of your child/person you care for (e.g. mother, father, grandparent, sibling, or carer), depending on your agreement. This ambitious survey will be repeated several times over the next few years. Our hope is that many families will choose to take part at multiple points so that we can see how responses change over time and get a much better insight into development in genetic syndromes, neurodevelopmental conditions, and intellectual disabilities across the lifespan.