Average age of onset is 35 to 55 years, but in
1% of cases the disease manifests during the first decade of life.
Affected children develop normally until 4 to 9 years of age. Early signs
include changes in behavior and personality, diminished facial expression,
and slurred speech. Later presentations are progressive involuntary
movements of the face, tongue, and limbs, and abnormal eye movement.
Clinically, there are stiff limbs, dystonia, rigidity (more common with
early onset juvenile disease), and propulsive gait with involvement of
proximal muscles (patients may be mistaken for being drunk). Behavioral
problems may be the first noticeable issues, with patients being
argumentative, impulsive, or erratic. Later, tremor and generalized
tonic-clonic seizures typically resistant to anticonvulsants may occur.
Ataxia and other cerebellar signs are present in 50% of cases and
oculomotor apraxia in approximately 20%. Intellectual changes range from
moderate intellectual impairment to progressive dementia, and mental
depression with suicidal attempts is frequent. The course of disease is more
rapid in children (average of 8 years) than in adults (14-17 years). Death
usually occurs from aspiration pneumonia. There is no specific treatment for
Huntington disease, but drugs that relieve movement disorder are helpful.
Butyrophenone and phenothiazines provide the best results in movement
disorder control.