A Clinical Review on Huntington Disease

Abstract

Huntington disease (HD) is a progressive, fatal, neurodegenerative disorder caused by an expanded (Cytosine, Adenine, Guanine) CAG repeat in the huntingtin gene, which encodes an abnormally long polyglutamine repeat in huntingtin protein. HD is characterised by unwanted choreatic movements, behavioural and psychiatric disturbances and dementia. HD is an autosomal dominant inherited disease caused by an elongated CAG repeat (36 repeats or more) on the short arm of chromosome 4p16.3 in huntingtin gene. The longer the CAG repeat, and then the onset of disease is earlier. The mechanism by which neuronal degeneration and cell death are being generated in HD may include excitotoxicity, energy deficit, oxidative stress, inflammatory process and protein aggregation. In the brain, the basal ganglia are highly affected which organize motor movement. The disease is characterised by a primary progressive loss of medium spiny projection neuron in basal ganglia. When the disease develops before age 20, the condition is called juvenile HD. Management should be versatile and is based on treating symptoms with a view to improving quality of life. Medication and non-medical care for depression and aggressive behavior may be required.