This project involves the study of a novel familial neurodegenerative disorder, familial encephalopathy with neuroserpin inclusion bodies (FENIB). This disorder, which has a characteristic clinical course of progressive dementia and neurologic involvement, was initially defined in one extended family. Neuroserpin is the gene for this disorder and a mutation is present in this large kindred and four additional families/cases. This protocol will characterize the clinical phenotype, delineate the natural history of the disorder and explore genotype/phenotype correlations in the index family and possibly in other reported cases. Families with immunohistopathologically-neuroserpin positive neuronal inclusions on autopsy/biopsy in an affected member(s), neuroserpin mutation-positive proband, or with familial presenile dementia with neurologic features consistent with the original FENIB family will be enrolled.

• INCLUSION CRITERIA:

Patients with a family history of early-onset progressive dementia or decline in cognition and neuronal inclusion bodies which are immunohistopathologically consistent with neuroserpin inclusion bodies.

Children with progressive dementia and myoclonic epilepsy which is consistent with the reported clinical course in pediatric patients or children with the clinical phenotype who on autopsy demonstrate neuronal inclusion boidies which are immunohistopathologically consistent with neuroserpin inclusion bodies.

Family members at risk, of at least 18 years of age, including first degree relatives of affected patients and the adult offspring of these first degree relatives.

In rare instances probands and their at risk family members with known presenile dementia and a neurologic course typical of that seen in FENIB will be enrolled.

We may also enroll offsite individuals who have any of the above findings, but are too medically fragile to travel to the Clinical Center and for whom a durable power of attorney (DPA) is available. The physical examination and laboratory research studies will be performed by the Investigator(s) and all clinical studies will be done in a local accredited hospital.

Family members either not at risk and unaffected spouses may enroll primarily for genetic linkage information. These individuals will contribute a blood sample for molecular analysis only. Those unwilling to travel may also provide a blood sample only. No clinical studies will be performed on individuals from this category.

EXCLUSION CRITERIA:

Another diagnosis of presenile demential is made by a physician including but not limited to: 1) Huntington Disease, 2) Parkinson Disease/Diffuse Lewy Body Disease, 3) Familial Alzheimer Disease with known mutations in presenilin 1, presenilin 2 or beta-amyloid precursor protein, 4) Lafora Body Disease, 5) Pick's Disease, and 6) fronto-temporal dementia.

A Durable Power of Attorney is not available in a human subject that is not medically competent to give consent.