What Is Juvenile Onset Huntington Disease (JHD)?
Juvenile Onset Huntington Disease (JHD) is a form of Huntington disease (HD) that affects children and teenagers. Huntington’s disease is a hereditary neurodegenerative disorder that is characterized by progressively worsening motor, cognitive, behavioral, and psychiatric symptoms. JHD is caused by a mutation of the huntingtin gene called a “CAG repeat expansion”. The mutation results in gradual neuronal degeneration in the basal ganglia of the brain, which is responsible for coordination of movements, thoughts, and emotions. As JHD progresses, other regions of the brain undergo neuronal degeneration with diffuse and severe brain atrophy that is comparable to late stage Alzheimer’s disease.
Presentation of JHD includes changes in personality, coordination, behavior, speech or ability to learn. Physical changes include rigidity, leg stiffness, clumsiness, slowness of movement, tremors or myoclonus. In comparison with adult HD, seizures and rigidity are common, and chorea is uncommon.
Predisposition and typical initial symptoms of Juvenile Onset HD include:
- Positive family history of HD, usually in the father
- Stiffness of the legs
- Clumsiness of arms and legs
- Decline in cognitive function
- Changes in behavior
- Changes in oral motor function
- Chorea in an adolescent
- Behavioral disturbances
Onset and Progression
JHD usually has a more rapid progression rate than adult onset HD; the earlier the onset, the faster JHD progresses. Death often occurs within 10 years of JHD onset, as opposed to 10-25 years in adult onset HD.
There is no cure or treatment to stop, slow or reverse the progression of JHD. Medications may be prescribed to manage symptoms. A child psychiatrist or behavior management specialist may address behavior disorders. A speech language pathologist may evaluate communication and swallowing problems. A nutritionist may be consulted to address nutritional needs as the disease progresses. Assistive devices such as wheelchairs, helmets, and communication boards may be used for safety, and to improve quality of life.
It is suggested that you contact your closest HDSA Center of Excellence if you have reason to suspect a case of JHD.
Social Security’s Compassionate Allowance Designation for Juvenile Onset HD
Social Security has an obligation to provide benefits quickly to applicants whose medical conditions are so serious that their conditions obviously meet disability standards. Compassionate Allowances are a way of quickly identifying diseases and other medical conditions that invariably qualify under the statutory standard for disability. The Compassionate Allowances program fast-tracks disability decisions to ensure that Americans with the most serious disabilities receive their benefit decisions within days instead of months or years.
Suggested Medical Evidence of Record for Evaluation
A diagnosis of Juvenile Onset HD (JHD), as well as clinical information documenting neurological or cognitive changes is required to meet the Compassionate Allowance listing.
The preferable sources of this information are the clinical records from the treating primary physician, neurologist, or psychiatrist including:
- Treating physician records documenting progression of motor, cognitive, and psychiatric symptoms, family history, and abnormal neurological exam findings consistent with juvenile onset HD
- Laboratory testing showing a fully-penetrant CAG repeat expansion in the HD gene (>39 CAG repeats).
- Brain imaging providing supporting evidence
- Psychological or psychiatric reports including neurocognitive testing
- School records providing supporting evidence.
To learn more, click on the links below to download PDF versions of informative and in-depth HDSA publications: