In Huntington's chorea all of the following can be found except

(C) Dysmetria # Huntington's Disease is a fatal autosomal dominant disorder characterized by progressive motor, emotional and cognitive dysfunction.> Onset is typically between the ages of 35 and 45 years.> It is caused by mutations in the Huntington's gene on the short arm of chromosome.> Pathophysiology of Huntington's disease> Loss of the intrastriatal GABA-ergic and cholinergic neurons, ii. The loss of the GABA-ergic pathway to the external--> Pallidum releases inhibition, permitting the hyperkinetic features of the disease to develop, iii. Degeneration of the nigrostriatal dopaminergic system causes Parkinson's disease (see below).> Clinical features of Huntington's disease:> Hyperkinetic choreiform movement, ii. Speech is slurred, iii. Progressive dementia.> Neurotransmitter involved in nigrostriatal pathway is Dopamine.> Dysmetria is a condition in which disturbance of the power to control the range of movement in muscular action.