Spinal and bulbar muscular atrophy

Spinal and bulbar muscular atrophy, popularly known as Kennedy's disease, is a rare, adult-onset, X-linked recessive lower motor neuron disease caused by trinucleotide CAG repeat expansions in exon 1 of the androgen receptor gene, resulting in both loss of androgen receptor function and a toxic gain of function. Affected males experience progressive muscle weakening, bulbar deterioration and lower motor neuron loss over decades, including involuntary muscle twitching, cramping and, as the condition advances, difficulty with speech and swallowing. Female carriers of the mutation typically remain asymptomatic. No cure currently exists, though supportive care can help maintain mobility and prevent complications. The condition is diagnosed by counting the number of CAG repeats in the androgen receptor gene and is worked within neurology.