For each participant, 10 ml of blood for lymphoblastoid cell line immortalization, 10-20 ml blood for DNA extraction, or two buccal swabs. If gene identified, blood samples from children to identify the children affected with this gene will be obtained. When available, biopsy tissues for extracting DNA, RNA, protein, or for cell biological studies will be obtained. Human genomic DNA will be prepared from peripheral blood lymphocytes, biopsy tissue, or cell lines derived from Epstein Barr virus transformed lymphocytes 15. DNA will be used for a variety of purposes including linkage analysis and mutational screening.