HD inheritance is characterized by anticipation. Successive generations, especially with paternal inheritance, tend to have a greater number of CAG repeats and thus an earlier age at onset.
Juvenile HD, also called the Westphal variant, presents before age 21 years and accounts for less than 10% of all cases of HD. Juvenile HD typically presents with dysarthria, difficulty walking, and cognitive and behavioral changes. Over time, parkinsonism (bradykinesia or akinesia and rigidity) and seizures develop. Chorea and dystonia may occur later in the disease course. The disease progresses more rapidly in children than it does in adults, and patients survive on average 8-10 years following symptom onset.
For more information, see OMIM.
G10 – Huntington's disease
58756001 – Huntington's chorea
- Sydenham chorea (see rheumatic fever)
- Huntington disease-like 1 or Huntington disease-like 2
- Chorea gravidarum
- Wilson disease
- Parkinson disease or atypical parkinsonism
- Tourette syndrome – not associatd with chorea
- Creutzfeldt-Jakob disease
- Frontotemporal dementia
- Spinocerebellar ataxia type 17 – cerebellar ataxia more prominent than chorea
- Multiple sclerosis
- Systemic lupus erythematosus
- Benign hereditary chorea – chorea is not progressive and not associated with dementia
- Psychiatric disease
- Drug-induced movement disorder