Oral Bacteria and Immune System Problems Involved in Gum Disease (Periodontitis)

Background: \- Gum disease is a condition in which the tissue around the tooth root becomes swollen and infected. This condition can cause tooth loss if it is not treated. Who gets gum disease and how bad it will be depends on (1) the different bacteria in the mouth and (2) how the immune system of an individual handles these bacteria. Researchers want to look at the oral bacteria and genetic immune problems of different people to learn how these affect gum disease and other conditions of the mouth. Objectives: \- To study how immune system problems may lead to problems in the mouth, including gum disease. Eligibility: * Children and adults at least 7 years of age who have genetic problems with their immune system. * Healthy adults that have periodontal disease * Health adults that do not have periodontal disease Design: * This study will involve a screening visit and a study visit. * Participants will be screened with a medical history, blood work and a full oral and dental exam, including dental x-rays and photos. * The study visit will involve collection of blood, urine, and other samples, including saliva, plaque, and gum swabs. Any abnormal tissue will sampled for a biopsy. Additional oral and dental exams will be performed. Participants will also answer questions about any current medical or dental problems.