RecruitingInvestigations of Juvenile Neuronal Ceroid LipofuscinosisBackground: CLN3, or Batten disease, is a genetic disorder. This deadly disease leads to decline of brain and nervous system functions. Symptoms of CLN3 typically occur between 4 and 7 years of age. They include changes in how a person sees, thinks, and moves. CLN3 can also cause seizures. No effective treatments for the disease are yet known. There is limited testing of potential therapies. Researchers want to study CLN3 more so they can improve future therapies. Objective: To identify clinical or biochemical markers that can be used as therapeutic outcome measures for CLN3. Eligibility: People with CLN3. It must be based on Two CLN3 mutations OR One CLN3 mutation AND findings seen with a powerful microscope Family members of a person with CLN3. Design: Participants will have already been referred to NIH for CLN3 evaluation. If participants agree to do the study, they will: 1. give spinal fluid, blood, urine, and skin samples. They may provide other samples if they were already collected. These may include cells, surgical specimens, and DNA. 2. will be seen by multiple healthcare specialists. Participants may provide medical records or photos. Participants will sign a release of medical records form.P Researchers may send samples or clinical data to other investigators. For research testing, the samples will not include the participant s name. For a test in a clinical lab, researchers will include the participant s name. These results will become part of the clinical record at NIH.