Association between autoimmune thyroid disease and familial Alzheimer's disease.

OBJECTIVE

To determine the prevalence of autoimmune thyroid disease in Familial Alzheimer's Disease kindreds and to ascertain whether there is any evidence for genetic linkage between the two conditions.

DESIGN

Retrospective study of Familial Alzheimer's Disease kindreds.

PATIENTS

Seventy affected and unaffected family members from 12 kindreds.

MEASUREMENTS

Anti-thyroglobulin and anti-microsomal autoantibody status was determined using an enzyme-linked immunosorbent assay. Thyrotrophin levels were determined by an immunoradiometric assay.

RESULTS

Of the family members, 41.4% had evidence of autoimmune thyroid disease, with significant co-segregation between the presence of thyroid autoantibodies and the development of Alzheimer's disease (P less than 0.01).

CONCLUSIONS

This study demonstrates a very high prevalence of autoimmune thyroid disease in Familial Alzheimer's Disease kindreds and suggests that a genetic factor contributing towards the development of autoimmune thyroid disease may be located on chromosome 21 within close proximity to the Familial Alzheimer's Disease gene.