Kennedy's disease is caused by a trinucleotide repeat expansion in the androgen receptor gene

Patients with Kennedy's disease usually receive a definitive diagnosis in a clinical molecular genetics laboratory. This requires DNA extraction from blood, followed by testing the gene that causes Kennedy's disease

yes

Kennedy's disease is a neurodegenerative disorder that is slow in its progression. It is likely that individuals will become wheelchair bound during the later stages of the disease

Addison's disease.

President Kennedy had it.