[Cognitive disorders in patients with Huntington's disease]

Huntington s disease has been clearly recognized since 1872. It is characterized by the appearance of a motor disorder (chorea) accompanied by selective cognitive deterioration which is not interfered with by aging.

Since the genetic defect causing it has been identified (expansion of CAG triplets on the IT 15 gene of chromosome 4) it has been possible to study families from the preclinical stage (asymptomatic persons who carried the mutation) to the stage of full development of the clinical syndrome. The behaviour disorders most often seen in these patients are depression, mania, schizophrenia, paranoia, anxiety, obsessive and obsessive compulsive disorders although other disorders may also occur. Different clinical forms of motor disorders and dementia have been reported in relation to the age of onset of the symptoms. The commonest cognitive symptoms are defects of attention, memory, planning, sequencing and visuo spatial deficits, as occurs in subcortical dementia. Our objective is to present the different clinical forms of the disorder according to the age of presentation, implication of the symptoms, severity of the genetic defect (number of CAG triplets) and to describe the study made of asymptomatic carriers so as to be able to detect incipient cognitive deterioration in these persons.