Spinal and Bulbar Muscular Atrophy

• Etiology of KD

  X-linked neuromuscular disorder Cytosine, adenine, guanine (CAG) repeats in androgen

  receptor gene
• Pathophysiology: degeneration of LMN, additionally may experience extra motor neuron features
• signs and symptoms: Neuromuscular symptoms neuromuscular atrophy 2% each year, difficulty with walking, increased falls, muscle cramps, tremors, decreased deep tendon reflexes
• later on may present with dysarthria, dysphagia
• multi-system effects: sensory, autonomic, CNS, metabolic, hormonal (androgen sensitivity), cardiac
• prognosis: typically associated with normal life expectancy, slowly progressive, over time muscle atrophy becomes more prominent, 1/3 of affected individuals will require a wheelchair 20 years after diagnosis
• medical management: no current disease-modifying treatments, supportive multidisciplinary care
• epidemiology: worldwide prevalence 1 per 300,000 males, those with European or Asian ethnic background