Patients who enter the study will be asked to provide us with their medical records related to their condition. Affected individuals and their unaffected family members will also be asked to have a small amount of blood drawn on one occasion. DNA will be directly extracted from a portion of the sample. Additionally, white blood cells will be collected from another portion of the sample to create a permanent cell line. These cells will be frozen for future use in these studies. Occasionally we may also obtain skin cells, cheek cells, discarded tissue from surgery, a semen sample or cell lines that have already been established in a cell bank in NIGMS (National Institute of General Medical Sciences /www.nigms.nih.gov/). We will use these samples to study mutations in selected genes.