What is Kennedýs Disease?

It is an X-Linked Spinobulbar Muscular Atrophy .
Symptoms begins in males in midadult life
The main clinical manifestations are 

• Lower motor neuron disorder in which there is progressive weakness and wasting of limb and bulbar muscles 
• Features of androgen insensitivity manifested by gynecomastia and reduced fertility  .

Difference with ALS 
Two findings distinguishing this disorder from ALS are

• The absence of signs of pyramidal tract disease (spasticity) 
• The presence of a subtle sensory neuropathy in some patients. 
• Gynecomastia is also a differentiating features 

Genetic abnormality
The underlying molecular defect in kennedy disease is an expanded trinucleotide repeat (-CAG-) in the first exon of the androgen receptor gene on X chromosome..There is an inverse correlation  between the number of -CAG- repeats and the age of onset of this disease. Genetic abnormality is detected with DNA testing 

What is the prognosis of ALS?

Average survival is 3-5 years after the onset of first symptom
Cause of  death are respiratory failure and insufficiency
Bulbar onset MND has worst prognosis, median survival is 20 months and 5% survive 5 years after the onset
Spinal onset MND has median survival  of 29 months and 15% survive 5 years after the onset
Short survival is associated with the following
Survival in ALS is depended on clinical and laboratory values
Clinical factors that determine the prognosis

• Increasing age 
• Recent significant weight loss 
• Short time from onset to diagnosis 
• Rapid rate of strength & respiratory loss during 6 months after diagnosis 
• Respiratory failure 
• No gastrostomy 

Laboratory factors that determine the prognosis are 

• Poor pulmonary function < 60% of predicted 
• Serum chloride: Falling; relation to poor nutrition 
• EMG 
• Low CMAPs 
• Decrement on RNS 
• EMG: Marked jitter; Low fiber density 

What is the pathology of MND

• In MND there is  loss of large motor neurons in spinal cord & brainstem
• Gliosis
• Spheroids are interwoven disorganized neurofilaments in proximal axons
• Bunina bodies are intracytoplasmic inclusion bodiesi neurons
• There is  loss of giant Betz cells , other neuronal loss in DRG & Clarkes’ nucleus
• 1/3 of motoneurons are destroyed before muscle atrophy becomes apparent
• Peripheral nerve shows secondary degeneration of axons & myelin
• Surviving motoneurons will develop collaterals branches
• Atrophy of the degenerated muscles is a prominent finding

What is motor neuron disease?

Motor neuron disease is a terminal neurodegenerative disease

Motor neurone disease is suspected in the following condition

• Progressive neurological illness
• Incurable
• Rare occurance
• Group of related diseases
• Motor neurones are affected
• Patient usually present with upper and lower limb weakness, speech and swallowing difficulties and breathing difficulties

Every person develops the disease in a different way

Symptoms experienced by a given patient depends on the area of nervous system affected 

90% - 95% of people have the sporadic form. 5-10% have Familial.

This is an adult Illness with most people are over 50. Onset and progression of MND is variable.

Average survival is 2-5 years from onset of first symptoms. 

There is no cure but symptom management and medication   may improve quality or prolong life.

Individual lifetime risk is 1 in 400

Men affected 1.5 times as often as women