Patients age 2 or older with GCD or other phagocytic disorders or cystic fibrosis may be eligible for this study. Participants (or a parent or guardian) will complete questionnaires including personal information such as age, gender and marital status, a family medical history, and information on their illness. Patients will be given various psychological and intelligence tests, and they and their parents or guardians will be interviewed by a child psychiatrist. The tests and interviews take a total of about 5 hours and are given in two or three separate sessions.