Early symptoms of juvenile Huntington’s disease

juvenile huntington

The early symptoms of juvenile Huntington’s disease (JHD) appear before the age of 20, during childhood or adolescence, and account for 5% to 10% of all Huntington’s disease (HD) cases. This condition is inherited and though the genes that cause it are present since birth, symptoms usually manifest between 30 and 40 years of age. JHD is an entirely different beast than adult-onset Huntington’s; not only does the disease begin earlier but also presents faster progression. Furthermore, the symptoms and the ways in which they affect the neurological and physical development of patients are different as well.

The early signs of JHD include:

·         Rigidity in the legs.

·         Clumsy arms and legs.

·         Cognitive function decline.

·         Behavioral changes and disturbances.

·         Chorea in adolescents.

·         Seizures.

Cognitive function decline

Most children with JHD are able to walk and talk normally before the onset of symptoms. However, the degenerative nature of the condition means they will lose the cognitive or motor skills they had learned up to that point, such as speech, reading, math, throwing a ball, swimming or riding a bicycle. This becomes apparent in school-aged children as a decline in school performance, as well as in loss of attention and concentration, which often leads to an ADD diagnosis.

Behavioral disturbances

These are common in both children with and without Huntington’s disease. In the former case, though, aggressive or disruptive behavior associated with HD is commonly accompanied by changes in cognitive function and motor disturbance. Behavioral problems – such as arson, theft, sexual promiscuity, physical or sexual abuse of younger siblings, severe drug or alcohol abuse, and depression with suicide attempts – may be the only sign in adolescents, but one that may lead to psychiatric hospitalization, suspension from school, or involvement with law enforcement agencies.


Unlike adults, stiffness of the legs, walking on the toes, or scissoring of the gait are early signs of juvenile Huntington’s disease, as are clumsiness of hand and arm movements, thickness of speech, drooling, and poor oral motor control.


Estimated to occur in approximately 25% of JHD patients though they may have a number of other causes.


The involuntary movements that characterize chorea are more common in adults than in small children. However, teenagers are more likely to present this as a symptom.



As we mentioned above, early-onset and adult onset HD are different, but they also share some similarities.

Juvenile HD


Adult HD



·         Progression to dementia.

·         Personality changes such as irritability and outburst of bad temper (mostly but not always a result of the difficulty of coping with the condition and not actual symptoms).

·         Neurological damage.


·         Most adult patients experience chorea.

·         Most juvenile patients experience seizures.

·         Time from onset to death is 10-30 years in adults and within 10 years in children.



Note that the early symptoms of juvenile Huntington’s disease are not only different from those of adult onset HD, but may also vary from one child to another. Furthermore, as indicated previously, it may be easy to diagnose it as attention deficit disorder. However, genetic testing offers an almost 100% accurate and simple method for diagnosing JHD. A child with early-onset HD more than likely has a father rather than a mother who also has Huntington’s disease. This alone is not enough to predict an outcome, though. As it turns out, the child may present symptoms of the condition before the father does, or the father may have died before his symptoms appeared, or the children may have inherited the healthy copy of the gene that causes HD.

Genetic material form a blood sample can be isolated to show whether the child has two normal HD genes – in which case he or she will not develop the condition nor pass it to his or her own children – or one abnormal gene – meaning they will develop HD at some  point, if not already. The abnormality in the gene is known as a CAG repeat expansion; 35 repeats or less is normal, while more than 35 can lead to Huntington’s disease. Despite the ease and accuracy of genetic testing, prematurely testing a child can lead to risks such as:

·         Incorrectly attributing of symptoms to HD.

·         Failing to make the correct diagnosis.

·         Stigmatization of the child.

·         Insurability.

·         Employability.

·         Psychological and social effects on the child.

That is partly the reason that a physician – preferably an adult neurologist specialized in movement disorders or HD instead of a pediatric neurologist who may not be familiar with the condition – should examine the patient’s neurological, behavioral, and functional problems before considering genetic testing. Tests of memory, developmental skills, and intelligence can assess strong and weak areas, suggest strategies for management and provide a baseline for comparison later, while computerized tomography (CT), magnetic resonance imaging (MRI), and routine blood tests can rule out other conditions. When most, if not all, of the signs point to HD, then and only then should genetic testing be conducted. If necessary, the doctor should examine the child twice, 6-12 months apart before proceeding to diagnostic testing of the HD gene. This is test can’t establish the cause of the symptoms, which is why it should be limited to children who clearly have clinical symptoms and a course that is consistent with Huntington’s disease. Thus the steps to arrive at a diagnosis of JHD are as follows:

·         History of motor, behavioral, and cognitive function changes.

·         Family history of Huntington’s.

·         Anomalous neurological examination

·         Abnormal results of neuropsychological tests.

·         Genetic testing confirming an abnormally long CAG repeat sequence.

·         Family counseling.

Both early and adult-onset HD forms of the condition are chronic and incurable conditions, meaning that the early symptoms of juvenile Huntington’s disease will continue to be experienced – along with other, more severe symptoms. However, therapy can help the patient adapt to the changes and limitations that are bound to come up.

Therapeutic interventions for JHD

Physical therapy

·         Home/school exercise program

·         Gait evaluation

·         Management of rigidity and spasticity

·         Safety evaluation

·         Assistive device training

·         Seating for the classroom

·         Reassessment of disease as it progresses

Occupational therapy

·         Safety evaluation

·         Assessment of daily living activities

·         Assistive devices

Speech language therapy

·         Outpatient or home speech therapy/oral exercises

·         Training with assistive devices

·         Dysphagia assessment

·         Choking avoidance strategies

·         Modification of food textures and types, eating/feeding strategies

Public health nurse home visit

·         Room-by-room assessment of the home

·         Attention to mobility

·         Safety

·         Assistive devices

·         Need for remodeling (for instance to accommodate a wheelchair)

·         Accessing emergency services

Dietary consultation

·         Assessment of ideal body weight, dietary habits, food preferences

·         Identifying unhealthy habits, obsessions, or food-related behavioral problems

·         Instruction in preparing modified diets

·         Monitoring weight and calorie intake.

·         Information about gastrostomy tube feeding

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