Huntington's Disease Diagnostic Criteria Needs Updating!


Looking back over the years, I can honestly say that much has evolved pertaining to education, information, and resources for Huntington's' disease. Many advancements have come through the years - research, care, and support. The physical attributes of Huntington's disease (Chorea) can now be "controlled" with medications: in previous years, Tetrabenazine/Xenazine, and most recently, AUSTEDO® (deutetrabenazine). These pharmacological advancements for the movements associated with Huntington's disease must be celebrated. However, what happens when patients do not manifest Chorea, yet they undoubtedly suffer from what used to be considered "softer symptoms" of Huntington's disease?


So why should the diagnostic criteria for Huntington's disease be updated?


Let's first examine the current diagnostic criteria for Huntington's disease as per the Movement Disorders Society:


"As part of a Task Force of the Movement Disorders Society, we therefore suggest that expanded diagnostic criteria for HD should be adapted to better reflect the natural history of the disease, to facilitate the conduct of clinical trials in premanifest subjects targeting prevention of neurodegeneration, and to facilitate earlier symptomatic treatment. We propose a revised set of criteria for HD diagnostic categories in the International Classification of Diseases to reflect our current understanding of HD natural history and pathogenesis. We suggest, as an initial proposal for discussion, that individuals with confirmed CAG expansion in Huntingtin (i.e., “genetically confirmed”) should be categorised as either “presymptomatic” (i.e., no clinical signs of symptoms and no functional disability),” “prodromal” (i.e., some subtle motor or cognitive changes representing a decrement from baseline and causing subtle subjective or objective difficulties) or “manifest” (i.e., clear motor and cognitive changes representing a decrement from baseline and causing significant subjective or objective disability. We suggest that depression be left as a separate diagnosis, since it can occur at any time during an individual’s lifespan, not be clearly related to HD onset, and should itself be the focus of active attention and treatment. However apathy and irritability, and other personality changes characteristic of HD may be considered when diagnosing prodromal and manifest HD. For individuals “not genetically confirmed,” we would propose categories of “clinically at risk,” “clinically prodromal,” and “clinically manifest”. " Link to quote by Christopher A. Ross and Ralf Reilmann.

Although the diagnostic criteria were chiseled "in stone" long ago, it is crucial that we as a community provide feedback to bring about change. When I coined the phrase, "Huntington's disease is not a one-size-fits-all disease" in early 2011, I meant it. Thousands of my peers quickly understood the truth behind those words. For years I have held many conversations with people across many countries, but our voices remained unheard.


Let us continue to remind ourselves of the question I put forth at the beginning of this article. What happens when patients do not manifest Chorea, yet they definitely suffer from what used to be considered "softer symptoms" of Huntington's disease?


In September 2020, WeHaveAFace launched an international survey: "Should the diagnostic criteria for Huntington's disease be reviewed and updated?" After several years of patient and caregiver conversations, we concluded that too many patients were being turned away from doctors because they did not meet the current diagnostic criteria (motor skills / Chorea). We decided to gather data to provide a comprehensive report to leading medical professionals in the field. WeHaveAFace Senior Medical Advisor, Dr. Herwig Lange of the George Huntington Institute, is overseeing this process. Preliminary results from the survey report rapid saturation (Saturation occurs when redundancy is reached in data analysis and signals to researchers that they may cease data collection). Simply, the community as a whole wants the diagnostic criteria to be updated and changed. The data not only speaks for itself, but the comments provided within the survey speak volumes.


Nowadays, it is widely recognized that many doctors have already made "tweaks" to the current diagnostic criteria. I personally know many of these medical professionals, and thankfully patients are finally being tested and diagnosed without chorea, but with other symptoms related to Huntington's disease. Inasmuch, many of our doctors are acknowledging and diagnosing patients with <40 CAG repeats (35-39). We must continue to treat Huntington's disease individually.


Again: What happens when patients do not manifest Chorea, yet they definitely suffer from what used to be considered "softer symptoms" of Huntington's disease?