Huntington’s disease

Huntington’s disease is a degenerative and hereditary disease which causes the destruction of neurons in the subcortical area (located below the cortex). It is linked to an anomaly discovered on chromosome 4.

This neurological condition combines cognitive deterioration as well as mental disorders with involuntary and disordered muscle movements (chorea). This rare disease affects about one in 10,000 people. Transmission of the inherited condition is of the autosomal dominant type. In other words, if it carries the genetic anomaly, only one carrier of two parents is enough to transmit the disease.

The first symptoms of Huntington’s disease usually appear between 30 and 45 years of age. However, there are early forms of the disease that can manifest at 15 or 25 years. In the beginning, the mental disorders caused by the condition are similar to a depression associated with a suicidal tendency. The disease will be diagnosed when researching the patient’s family history.

Even if the manifestations of the affection differ according to the patient, the neurological degeneration is detected through:

• Motor symptoms, including chorea (irrepressible and irregular movements accompanied by spasms or distortions),

• Balance problems as well as swallowing and speech disorders,

• Cognitive symptoms, including impaired memory, difficulty in thinking or performing multiple tasks, slowness in acquiring or processing information, and cognitive impairment (causing subcortical dementia syndrome)

• Psychiatric symptoms such as agitation, anxiety, disinhibition, aggression, depression, etc

Many elements make it possible to guide the physician’s diagnosis towards Huntington’s disease, in particular:

• The appearance of serious coordination disorders and choreaic movements

• The progressive installation of a perceptible intellectual weakening through difficulties in recognizing loved ones, problems of disorientation as well as disorders of attention, memory, reasoning, language, behavior, and mood.

• The existence of family members with or having similar symptoms (the investigation focuses on undiagnosed cases).

Neuropsychological tests are the first step in the differential diagnosis. Once other causes of dementia are eliminated, genetic testing can confirm the presence of the abnormality. If the patient is the first to present these symptoms in their family, the doctor conducts a CT scan and a brain MRI. Huntington’s disease usually causes atrophy of the frontal lobe and coded nuclei as well as hypertrophy of the frontal horns.

1. https://www.eaneurology.org/fileadmin/user_upload/22_E-PC-EAN-role_of_neurology-Deuschl-FINAL.doc

Fiche Huntington’s disease

• Author : Florian Reinaud, MD
• Date : Jun 15, 2017
• Author of revisions : Amine Morjane, MD
• Revision date : Jul 09, 2019