Revision of Diagnostic Criteria and Procedures for Huntington’s Disease
International HD Diagnosis Working Group
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What is Huntington’s Disease?
It is important to define Huntington’s disease. As per the National Institute of Neurological Disorders and Stroke (NINDS), Huntington's disease (HD) is an inherited disorder that causes brain cells, called neurons, to die in various areas of the brain, including those that help to control voluntary (intentional) movement. Symptoms of the disease, which gets progressively worse, include uncontrolled movements (called chorea), abnormal body postures, and changes in behavior, emotion, judgment, and cognition. People with HD also develop impaired coordination, slurred speech, and difficulty feeding and swallowing. HD typically begins between ages 30 and 50.
An earlier onset form called juvenile HD occurs under age 20. Its symptoms differ somewhat from adult onset HD and include rigidity, slowness, difficulty at school, rapid involuntary muscle jerks called myoclonus, and seizures. More than 30,000 Americans have HD. Huntington’s disease is caused by a mutation in the gene for a protein called huntingtin. The defect causes the cytosine, adenine, and guanine (CAG) building blocks of DNA to repeat many more times than is normal. Each child of a parent with HD has a 50-50 chance of inheriting the HD gene. A child who does not inherit the HD gene will not develop the disease and generally cannot pass it to subsequent generations. A person who inherits the HD gene will eventually develop the disease. HD is generally diagnosed based on a genetic test, medical history, brain imaging, and neurological and laboratory tests.
*NINDS description of HD is incomplete as it does not include the malfunction and loss of glial cells (cells essential to support and protect neurons), which are more frequent in the brain than neurons. The NINDS description also lacks information about the damage to cortical areas of the brain, leading to psychiatric, cognitive, and behavioral problems. These problems with HD are more relevant to patients and families in their everyday functions than motor symptoms (chorea) as per the feedback from our international survey.
Although a definition of Huntington’s disease can be found on the websites of every HD lay organization, HD Center, HD Healthcare Center, etc., to truly comprehend what Huntington’s disease is, it is paramount to have the insights and life experiences of patients, caregivers, and families who are directly affected. It is also imperative that the voices of Huntington’s patients, caregivers, and families are heard. These warriors are the natural experts! Sadly, the challenge that patients and families experience is the ability to receive a diagnosis of Huntington’s disease when it is needed. The global Huntington’s community has spoken, and it is time to have the current diagnostic criteria change to benefit the needs and lives of patients and families.
Note: As per EHDN (European Huntington Disease Network) a meeting took place in Vienna (2019) – a redefining of JHD (Juvenile-onset HD) was accepted. The publication (January 2019) is now defined as Pediatric Huntington’s disease. Read paper
Why is a revision needed?
History of last diagnostic criteria Review: 2009
Results: No change to diagnostic criteria
The American Academy of Neurology (AAN), and the Movement Disorder Society, have not effectively procured the support and needs of our Huntington’s patients and families. This must change.
The PREDICT HD study, conducted over twelve years and funded by the NINDS (National Institute of Neurological Disorders and Stroke), found that behavioral and cognitive changes occur decades before the movement disorder, yet neurologists have been slow at best in incorporating the research into their practice and diagnosis. PREDICT HD looked specifically at recognizing early HD with the expectation that data would assist in the development of disease-modifying therapies.
Another point to consider is the recent updating of the diagnostic criteria for ALS (amyotrophic lateral sclerosis), which sought to improve the early diagnosis of the disease when clinical symptoms were minimal so affected patients could access various therapies and sustain a higher quality of life. The consensus group agreed that ALS was a progressive disorder. The new definition of ALS is Progressive motor impairment, documented by history or repeated clinical assessment, preceded by normal motor function. Upper and lower motor neuron dysfunction in at least one body region (in the same body region if only one body region is involved), or lower motor neuron dysfunction in at least two body regions. Investigation finds that excluded alternative disease processes.
This new definition raises a few points for diagnosing Huntington’s disease - it is a progressive disease leading to impairment in one or more of three distinct spheres – behavior, cognition, motor – that can be documented by history or repeated clinical assessment. But unlike ALS, at what point does each of those spheres meet a minimum measure of impairment?
If a Huntington’s patient is gene-positive, is 50% impairment in one or more spheres adequate for a diagnosis? The TFC (Total Functional Capacity) scale, created by Shoulson and Fahn, 1979, and then adopted by the HSG in 1996), is the main assessment tool of functional status in HD clinical care and research.
It has been used as the primary outcome measure in several clinical trials in manifest HD.
However, as per the TFC – the scale was designed to assess progression of HD in patients with manifest disease and accordingly emphasizes self-care, mobility, and independence. Is the TFC a reliable tool to assess this degree of impairment? How can documentation by healthcare providers be standardized so impairment observed/documented over time is reliable?
What effect does a diagnosis have for our patients who are gene positive? Does knowing with a 50% certainty provide a greater or lesser benefit to the individual? Will it make a significant difference in the choices our patients and families make? If a survey of the HD community supports the benefit of a definitive diagnosis with 50% certainty, then the voice of the patients and families must be included in any modifications made to diagnostic criteria. Some of the resistance to change is mired in paternal attitudes that persist in the medical community.
It doesn’t seem to matter if the physician is younger or older, many still cling to the idea that the patient doesn’t have sufficient knowledge to form an opinion even when the family may be actively educating the healthcare provider about Huntington’s disease in order to obtain a diagnosis.
Earlier diagnosis would open access to therapies that could improve the quality of life of our community, but the flip side of an earlier diagnosis might be denial of access to clinical trials. The Huntington’s community wants this to be considered since we are still lacking in any real therapy.
Current diagnostic criteria:
- It does not meet the needs of our patients and families.
- Excludes a large group of our patients who do not express overt motor symptoms (chorea).
- It does not effectively support our patients who have manifested: psychiatric and cognitive symptoms of Huntington’s disease.
UHDRS Q80 should be changed: Q80 diagnostic criteria (Motor, Cognitive, Behavioral, and Functional components) do you believe with a confidence level ≥99% that this participant has manifest HD? (0 = No, 1 = Yes)
Confidence level ≥99% should be changed to ≥50%
It must be made easier for a diagnosis to be given to patients who need it. Patients and families seek the following considerations for diagnostic criteria to be changed:
Vegetative Function: Bodily processes most directly concerned with the maintenance of life.
Sexual promiscuity / Hypersexuality / Hyposexuality
Sleep issues / Insomnia / Increased Sleep
Temperature changes of the body (Hot or Cold) / Sweat sleeps
Bowel and bladder problems
Appetite (normal/elevated/reduced -> weight loss)
Depression with the high rate of suicide
Anxiety / Social anxiety and/or withdrawal
OCB – Obsessive-Compulsive Behaviors / Perseverative Behaviors
Schizophrenia-like behavior / Paranoia / Hallucinations
Mania / Bipolar-like disorder
Irritability / Aggression
Issues with multitasking
Issues with memory
Denial (Individuals do not believe they have HD – denying the existence of HD)
Anosognosia (Individual unaware of having or showing symptoms of HD)
Training for neurologists in movement disorders, including Huntington’s disease, has not changed significantly in over twenty-five years – since the gene was actually located. Neurologists are still taught that HD is a movement disorder first, and other symptoms follow.
This specific topic on how little training medical professionals receive regarding Huntington’s disease was outlined within the 2019 award-winning documentary – “The Purple Road” (29:44 – 30:50), by WeHaveAFace.org.
As of 2019 what we found were the following:
Medical Schools: most often only 1-2 hours, mostly on biology and genetics of HD.
Internal Medicine for Family Practice Residency Training: at best, 1-2 hours.
Neurology Residency Training: only a few hours unless the trainee specifically requests it.
The Movement Disorder Fellowship Training: for many programs, this is still only a few hours, even in centers that have HD-specific clinics.
Psychiatry Fellowship Training: many programs offer no training in HD.
Post-Graduate Continuing Education: hasn’t been offered before 2010.
It is hard to get doctors to attend a course in HD, including Movement Disorder Neurologists, even when it is free.
Additional proof for necessary changes to take place was expressed in our first award-winning documentary - "The Huntington's Disease Project: Removing the Mask." The documentary took on the most sensitive subject matter relating to Huntington's disease. At that time is was taboo to remove the mask on topics that were hidden for decades (Pysciatric, cognitive, and vegetative), listed above. It was time to let patients and caregivers openly discuss what truly happens to patients and families - unsensored.
It has been noted that some neurologists are reluctant to diagnosis HD in the absence of movements since they continue to believe that there is little that can be done for the patient. As per the publication, “A Physician’s Guide to the Management of HD,” by the HDSA (Huntington’s Disease Society of America), observational studies have demonstrated that changes can occur prior to the development of motor symptoms. In fact, “A Physician’s Guide to the Movement of HD” notes that cognitive changes have been observed in 40% of individuals studied and are detectable in more than 70% of those close to a diagnosis of manifest HD. Several studies have suggested that cognitive and behavioral impairments are greater sources of impaired functioning than the movement disorder in persons with HD, both in the workplace and at home. Yet neurologists will not diagnosis without the movement disorder.
Patients / Family Feedback:
The endeavor and goal to change the diagnostic criteria for Huntington’s disease are driven by patients and families worldwide. WeHaveAFace.org, and its Senior Medical Advisor, Dr. Herwig Lange (George Huntington Institute of Germany), asked the international Huntington’s disease community to participate in an anonymous survey on October 13, 2020. The survey was shared via social media platforms (Facebook, Twitter, LinkedIn, Instagram, etc.), WeHaveAFace Global Times (electronic newspaper), WeHaveAFace TV, and WeHaveAFace global email database.
The Survey Question: “Should the diagnostic criteria for Huntington's disease be reviewed and updated?”
*In the survey, "other symptoms" pertain to depression, anxiety, behavioral issues, mood swings, physical abuse, social issues, alcohol/drug issues, suicidal thoughts/actions, apathy, sexual promiscuity, inability to hold employment/problems at work, etc.*
Data reported from the following survey questions:
- “Do you believe that Chorea should NOT be the only factor to receive a diagnosis of Huntington's when other
symptoms of Huntington's disease are present and affecting the individual?”
- “Chorea is not my/our main concern with HD.”
- “Me/my loved one experience memory, behavior, cognitive, and social issues.”
- “In the USA, without a diagnosis and medical coverage, I cannot afford to see a doctor.”
- “I/we believe that a person should receive the diagnosis without Chorea if they are suffering from other
- “I/we believe that if a person should have the right to know if they are positive or negative for HD.”
- “I/my loved one have thought of or attempted suicide.”
- “Do you believe that the current diagnostic criteria for Huntington's disease should be reviewed and updated?”
1,485 of our patients/caregivers participated, and saturation was reached via early review of data on November 15, 2020; however, the survey remained open until January 7, 2021, for additional data collection.
Overall: 95% of our patients and families surveyed agreed that the diagnostic criteria for Huntington’s disease should be reviewed and updated.
Participating countries: USA, Canada, Mexico, England, Scotland, Ireland, Germany, Finland, Australia
See survey results and read comments from our patients and families:
Dr. Hugh Rickards, Professor of Neuropsychiatry (National Centre for Mental Health, Birmingham, England), brought up a fundamental question for our patients and families. With Dr. Rickards’ question in mind, WeHaveAFace.org continued to move this mission forward and published an anonymous international poll on March 1, 2021. The poll was shared via social media platforms (Facebook, Twitter, Instagram, and email).
Dr. Rickards’s question was: “Why is a diagnosis of Huntington's disease important to you?"
On March 7, 2021, almost 4,000 individuals within the international Huntington’s community had voiced their opinion and participated. The poll closed on March 15, 2021, with over 4,000 individuals polled.
Participating countries: USA, Canada, Mexico, England, Scotland, Ireland, France, Germany, Netherlands, Italy, Australia, and Spain. See poll and stats:
Chart expressing Huntington’s disease community polling results:
Data from the three lowest polled responses:
My parent did not/will not get tested, but I want to know.
To participate in studies and trials.
To plan to have biological children.
International HD Diagnosis Working Group
Since November 2020, an international working group has been meeting monthly. Together we are working diligently on updating the current diagnostic criteria for Huntington’s disease.
Dr. Herwig Lange (George Huntington Institute), Dr. Ralf Reilmann (George Huntington Institute), James Valvano (WeHaveAFace), Louise Vetter (HDSA), Debra Lovecky (HDSA), Astri Arnesen (European Huntington Association), Dr. Jane Paulsen (University of Wisconsin, Madison), Dr. Hugh Rickards (National Centre for Mental Health, Birmingham), Dr. Travis Cruickshank (Edith Cowan University), Mayke Oosterloo (Maastricht University Medical Center, NL), Dr. Thomas Bird (HDSA CoE, University of Washington), Svein Olaf Olsen (IHA), Dr. Roger Barker (University of Cambridge, UK), Dr. Raymund A. C. Roos (Leiden University Medical Centre, NL), Dr. Ferdinando Squitieri (L'Unità Operativa di Neurogenetica, Roma, I)
Call to Action! We want your comments and feedback! The voices of our Huntington's community will help us change the current diagnostic criteria. It is time for change!
"Never doubt that a small group of thoughtful, committed citizens can change the world; indeed, it's the only thing that ever has." - Margaret Mead