GENETIC-ASPECTS OF ALZHEIMERS-DISEASE

Alzheimer's Disease (AD) is a neurodegenerative disease of the elderly characterized by severe loss of cognitive function. Even though the etiology of the disease remains unclear, a genetic component has been advanced. In 40% of families, AD may be considered to have a genetic pattern of familial aggregation, whereas in 60% of families AD is sporadically ocurring. In cases of familial aggregration, autosomal dominant inheritance has been observed in some patients. Genetic linkage studies using molecular genetic markers demonstrate linkage with markers on the long arm of chromosome 21. The gene that produces Beta amyloid protein precursor is also found in the same chromosome. Mutations in this gene have been described in some families. Other families present linkage with markers on chromosome 19. Recent studies have shown another gene that produces AD in Chromosome 14. The above mentioned findings support the hypothesis of genetic heterogeneity in AD.