What is the Origin of Kennedy's Disease?

The disease is named after the American neurologist William R. Kennedy, who first described the condition in detail in the 1960s. Its genetic basis lies in the expansion of a CAG trinucleotide repeat within the androgen receptor (AR) gene on the X chromosome. This genetic origin directly links the neurological symptoms to a defect in the body's ability to properly respond to androgens.

What is the Mechanism of Kennedy's Disease?

The underlying mechanism is the production of an abnormally elongated, unstable polyglutamine tract within the androgen receptor protein due to the expanded CAG repeats. This mutant AR protein misfolds and aggregates within the motor neuron cells, becoming toxic to them. Although androgens are essential for AR function, the mutant receptor fails to function correctly and instead contributes to the motor neuron death, leading to the characteristic muscle weakness and atrophy observed in affected individuals.

Kennedy’s Disease

Meaning

Kennedy’s Disease, formally known as Spinal and Bulbar Muscular Atrophy (SBMA), is a rare, X-linked inherited neuromuscular disorder characterized by the progressive degeneration of lower motor neurons in the brainstem and spinal cord. Clinically, it presents with slowly worsening muscle weakness and atrophy, particularly in the limbs and bulbar muscles, which control speech and swallowing. A notable endocrine feature is a variable degree of androgen insensitivity.