Huntington’s disease: Understanding the impact

Jennifer Simpson of the Huntington’s disease Society of America highlights the disease and how there is still a long way to go before it can be truly understood

Since the discovery of the gene that causes Huntington’s disease in 1993, exponential progress has been made in elucidating the true scope of Huntington’s disease, but there are still miles to go to truly understand the impact of symptoms of HD families. Huntington’s disease (HD), is an autosomal dominant neurological disease caused by an expanded CAG repeat in the Huntingtin gene. The disease is characterised by progressive functional decline and motor, psychiatric and cognitive symptoms, in addition to weight loss, sleep disturbances and dysregulation of the autonomic nervous system1. Each child of a person who carries the gene mutation that causes HD has a 50% chance of inheriting the faulty gene.

Cognitive and behavioral symptoms are most impactful to HD patients and families

In preparation for a Patient Focused Drug Development meeting with the U.S. Food and Drug Administration, the Huntington’s Disease Society of America (HDSA) surveyed the HD community in the U.S. on topics related to HD symptoms and treatments. Between two surveys, more than 3,600 responses were collected from individuals affected by HD, Juvenile Huntington’s disease (JHD) and caregivers for those with HD and JHD.

In reviewing the data collected, clear trends began to emerge between caregivers and HD/JHD patients alike. Caregivers responded most frequently that chorea was the most impactful symptom of HD (30%), but in aggregate, behavioral and cognitive symptoms were reported as the most impactful to their lives by more than 50% of both caregivers and HD/JHD patients2.

Huntington’s disease has long been classified as a movement disorder, though prodromal features encompass cognitive and behavioral symptoms of HD3. Although classified as “prodromal”, the cognitive and behavioral symptoms of HD are major elements of the disease and its impact on the individual and their families. Cognitive and behavioral symptoms can manifest as much as a decade before motor symptoms develop, and as a result often go undiagnosed as symptoms of HD. It is not uncommon for individuals with HD to be misdiagnosed with a variety of psychiatric disorders before being correctly diagnosed with HD at the onset of motor symptoms. Delayed diagnosis may unfairly disadvantage people with HD and cognitive-behavioral symptoms, especially in terms of accessing the kind of care and benefits people with HD really need to best manage the progression of their disease4.

For Huntington’s disease patients, treatment options are lacking

In the world of HD, treatment options are few and far between. As of the publication of this article, only two medications exist that are FDA approved for the treatment of HD, and both treat chorea symptoms associated with the disease. Currently, there are no disease- modifying treatments or cures. When surveyed on availability and efficacy of current treatments for cognitive symptoms of HD, more than 80% of respondents noted that they or their loved one were not taking any kind of medication for symptoms like deterioration of memory and thinking2. For behavioral symptoms like anxiety, depression and irritability, individuals responded most frequently that they or their loved one was not taking any kind of medication to treat those symptoms2. The lack of treatment options, especially for cognitive symptoms of HD, stands in stark contrast to the impact those symptoms have on the lives of people with Huntington’s disease.

Access to care early on is critical to managing Huntington’s disease

As patients with HD become symptomatic, it is key that those individuals have access to comprehensive care with doctors who are knowledgeable in HD. HD patients in early to middle stages of the disease need coordinated multidisciplinary healthcare services, including assessment of cognitive function and counselling by (neuro) psychologists, rehabilitation programmes, active physiotherapeutic interventions, speech therapist training and occupational therapy5. Lack of access to care for families with HD means unmanaged or poorly managed symptoms, higher rates of caregiver burnout, potential unnecessary hospitalisations and early entry into long-term care facilities.

With access to specialists knowledgeable in HD, families can avoid unnecessary additional emotional and financial burdens. In the U.S., HDSA has created a clinical care model through the Center of Excellence programme, awarding grants to HD clinics around the country to provide an all-in-one service center for families affected by Huntington’s disease. HDSA currently funds 41 Centers of Excellence around the U.S.

Expanded access to government programmes can help HD families

Individuals with HD access multiple forms of governmental support as their disease progresses. Because HD symptom onset commonly occurs during prime working years, many families are devastated financially, and need to rely on programmes like Social Security Disability Income (SSDI), Medicaid and Medicare. Utilising these programmes can help families access professionals like neurologists, neuropsychiatrists, speech therapists and physical therapists. Expansion of Medicaid programmes has resulted in a reduction of unmet need for mental health services, in addition to positive impacts on the budgets of states that expanded Medicaid as states no longer needed to use some of their general funds to pay for behavioral health treatment for the uninsured6. Individuals with HD are included amongst those who have benefitted from the expansion of programmes like Medicaid, and would further benefit from expedited access to Medicare through the Social Security Disability Income programme. HDSA has been advocating, alongside the HD community, for a waiver of the two-year Medicare waiting period for individuals who are disabled by Huntington’s disease and utilising the SSDI programme. The Huntington’s disease Parity act of 2017 is a bi-partisan solution to an HD shaped hole in the social safety net. It is one step of many to help ensure access to important behavioral health services and specialist neurologists who can assist families maintain quality of life for folks with HD for as long as possible. Although we currently have no cure for this disease, we do have the ability to allow individuals to access treatments to help them manage this debilitating illness. While we work on a cure and find hope for tomorrow, we have to ensure that families affected by HD can access the help they need today.

1 Vinther-Jensen, Tua, Larsen, I.U., Hjermind, L.E., Budtz-Jørgensen, E., Nielsen, T.T., Nørremølle, A., et al. A clinical classification acknowledging neuropsychiatric and cognitive impairment in Huntington’s disease. Orphanet J Rare Dis. 2014;9(1):114.

2 Simpson, Jennifer A., Lovecky, D., Kogan, J., Vetter, L.A., and Yohrling, G.J. “Survey of the Huntington’s Disease Patient and Caregiver Community Reveals Most Impactful Symptoms and Treatment Needs.” Journal of Huntingtons Disease 5, no. 4 (2016): 395-403. doi:10.3233/jhd-160228.

3 Stout, Jane C., Paulsen, J.S., Queller, S., Solomon, A.C., Whitlock, K.B., Campbell, J.C., et al. Neurocognitive signs in prodromal Huntington disease. Neuropsychology. 2011; 25(1):1-14.

4 Loy, Clement T., and McCusker, E.A. “Is a Motor Criterion Essential for the Diagnosis of Clinical Huntington Disease?” PLoS Currents, 2013. doi:10.1371/currents.hd.f4c66bd51e8db11f55e1701af937a419.

5 Van Walsem, Marleen R., Howe, E.I., Iversen, K., Frich, J.C. and Andelic, N. “Unmet needs for healthcare and social support services in patients with Huntington’s disease: a cross-sectional population-based study.”Orphanet Journal of Rare Diseases 10, no. 124 (September 28, 2015).https://ojrd.biomedcentral.com/articles/10.1186/s13023-015-0324-8.

6 Dey, Judith, Rosenoff, E., and West, K. “Benefits of Medicaid Expansion for Behavioral Health.” March 28, 2016. Accessed May 20, 2017. https://aspe.hhs.gov/system/files/pdf/190506/BHMedicaidExpansion. pdf.

Jennifer Simpson

Manager of Advocacy and Youth Programmes

Huntington’s Disease Society of America

www.hdsa.org

www.twitter.com/HDSA

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