Relationship between autoimmune thyroid disease Rand Alzheimer's disease.

Alzheimer's Disease (AD) is a particular form of degenerative dementia probably due to deposit in the brain cortex of a non soluble protein called beta-A4 amyloid in senile plaque form. beta A4 is an aberrant mutant proteolytic product of Amyloid Protein Precursor (APP) codified on chromosome 21. Trisomy 21 is responsible for Down's Syndrome (DS). Down's patients have been shown to develop a form of Alzheimer's after 50 years of age, and high blood levels of antithyroid antibodies are also present in a significant percentage of these cases. In the present investigation, antithyroid antibody titres have been studied by means of RIA in group of 34 AD patients. As compared to 30 non-demented controls, AD subjects showed a significant increase in the mean values of antithyroglobulin (TgAb) and antimicrosomial (MCSAb) autoantibodies. The physiopathological relationship regarding this association is discussed.