Significance of Dental Care
Adequate dental care is an integral part of maintaining healthy teeth and gums, which are vital not only for eating, but also for social communication. As a result, poor dental health can have both physical consequences (i.e. tooth decay, gum disease) and mental consequences (i.e. low self-esteem). Huntington’s Disease (HD) can often make dental care difficult for patients. The classic HD triad of motor, cognitive, and psychiatric clinical symptoms adversely impact the ability of patients to take care of their teeth and gums, leading to many dental and psychological issues.
Challenges In Dental Care for HD Patients
There is no genetic basis behind why HD increases the susceptibility of teeth to decay. However, largely due to the inhibiting symptoms of HD, HD patients have a higher clinical incidence of dental issues than normal. To this point, as HD progresses, there is an increase in the risk for cavities and periodontal disease, or infections of the structures around the teeth- such as the gums.
There are a variety of factors that contribute to this increased risk. For one, research has demonstrated that many HD patients benefit from a high-energy diet. Such a diet lends itself to high sugar intake. This sugar is processed by bacteria on the surface of teeth, and turned into acid that dissolves the tooth and causes tooth decay. Furthermore, as noted by the Huntington’s Association New South Wales, toxins freed by these bacteria can cause progressively worse irritation in the gums and eventually gum disease. These problems are exacerbated by a decrease in dexterity that patients with HD might experience, making it difficult to operate a toothbrush and dental floss.
Involuntary movements typical in HD patients can lead to bruxism, or grinding and clenching of teeth, which can cause them to deteriorate over time. Additionally, involuntary movements can make it difficult to stand still. As the disease progresses, patients might not be able to fully open their mouths, further complicating dental care. Dysphagia, or difficulty swallowing, may also develop with the progression of the disease and can make brushing teeth difficult.
Other factors can also contribute to HD patients not receiving or having access to adequate dental care. Common symptoms of HD, such as apathy and resentment, may contribute to HD patients not prioritizing their dental hygiene. Additionally, transportation to appointments, access to facilities, and the financial burden of dental care may pose substantial barriers for some people to access adequate treatment.
Furthermore, routine oral surgeries such as root canals can present with unique difficulties in HD patients. The use of anesthesia for surgeries generally presents with a higher risk for pulmonary aspiration (inhalation of the stomach contents) in HD patients due to chorea. As a result, any dental surgery requiring anesthesia requires careful consideration of many factors by the physician. This problem is accentuated by the tendency for HD to require anesthesia even for routine treatments that usually wouldn’t require it. A notable example is with routine dental fillings. They typically do not require anesthesia, but can be difficult to perform without anesthesia in late stage HD patients because of the chorea and behavioral complications that they may experience.
What Can Be Done?
While HD patients do experience unique challenges in dental care, poor dental health does not necessarily need to be a hallmark of the disease. There are many things patients and caretakers can do to maintain great dental health. For example, The Huntington Society of Canada advocates for preventative care in order to mitigate risks. This includes the continued support of caregivers, starting good habits early, and using alternatives to conventional dental care if need be.
Sources and Further Reading:
“Dental Care in Huntington Disease.” Huntington Society of Canada.
Lane and Manley, “The oral health and dental treatment of adults with Huntington’s disease.” Journal of Neurology, Neurosurgery & Psychiatry.
Manley et al., “Guideline for oral healthcare of adults with Huntington’s disease.” Neurodegenerative Disease Management.
“Oral Implications of Huntington’s Disease.” drcairo.com.
Rada, R., “Comprehensive Dental Treatment of a Patient With Huntington’s Disease: Literature Review and Case Report.” Special Care in Dentistry.
Saft el al., “Oral and dental health in Huntington‘s disease – an observational study.” BMC Neurology.
“The Importance of Dental Care in Huntington Disease.” Huntington’s New South Wales.
The following is a brief survey of HD-related research published during January-March 2020:
Gene therapy refers to the delivery of genetic material to cells in order to treat disease and is an area of active HD research.
In a February study published in Nature Communications, Wu and colleagues from Pennsylvania State University investigated the use of gene therapy to convert a type of glial cell called astrocytes into neurons in a mice model of HD. Mice treated with this novel therapy had a significantly longer life span and improved motor functions. These results indicate that gene therapy conversion of glia to neurons could be a feasible way to treat HD.
Antisense oligonucleotides are short strands of DNA that interact with messenger RNA, the precursors of proteins. Researchers have been investigating the use of antisense oligonucleotides (ASOs) to prevent the production of certain maladaptive proteins that cause disease and the technique has shown great promise for HD, which is caused by a mutant HTT protein. However, a major challenge for ASOs as a viable treatment is the difficulties in effective delivery to the brain.
In a January study published in Angewandte Chemie, a group of Japanese researchers investigated a method of ASO delivery to the brain that is less invasive than current methods. Their method involves the passage of ASOs across the blood-brain barrier, a very difficult-to- cross barrier between circulating blood and the brain, using careful glycemic control. Using glucose-coated polymeric nanocarriers, the researchers demonstrated efficient accumulation in brain tissue after intravenous injection and significant inhibition of non-coding RNA in mice. Their results show a novel method of ASO delivery to the brain in a noninvasive manner.
Autophagy refers to a cellular process that works to maintain homeostasis by eliminating unwanted and damaged molecules such as proteins. Researchers have been interested in utilizing this natural process in order to clear aggregates of misfolded proteins common in many neurodegenerative diseases. In the case of Huntington’s disease, many different genetic and pharmacological mechanisms have been used by scientists to induce autophagy and clear harmful aggregates of huntingtin protein.
In a January report published in Cells, a group of Italian scientists mainly from the University of Milan demonstrated a new way to induce autophagy and clear aggregates of huntingtin. Their study showed that regulation of an enzyme called glutamine synthetase 1 (GS1) is able to induce autophagy in a fruit fly model of Huntington’s disease and improve neuronal survival. These findings open up the opportunity for the development of new therapeutics for HD targeting GS1 in future research.
Advances in Understanding HD
Aberrant neuronal development refers to abnormalities in brain cell development and has been implicated in many neurological disorders such as Huntington’s disease.
A March report published in Stem Cell Reports by Smith-Geater and colleagues investigated aberrant development in adult-onset HD. Using induced pluripotent stem cells (iPSCs) from HD patients and controls, the researchers identified a mechanism that promotes aberrant neurodevelopment as well as preliminary evidence that specific components of a particular signaling pathway could be a counteractive therapeutic target.
In a January report, a group of scientists from the University of Southern California investigated the effects of treadmill exercise on a mouse model of HD. They found that the treadmill exercise resulted in increases in nitric oxide levels as well as improved mitochondrial function. These changes were also associated with improved motor performance. Their findings suggest that in a mouse model of HD, exercise could have a beneficial effect on motor behavior by counteracting deficits in mitochondrial function.
HD and Cardiac Arrhythmias
In recent years, there has been increasing evidence that HD patients could be at an increased risk for cardiac arrhythmias.
In a February study published in Human Molecular Genetics, Zhu and colleagues aimed to investigate this phenomenon in a mouse model of HD. Their findings were consistent with prior knowledge, indicating that mutant Huntintin protein (mHTT) can cause problems in cardiac conduction systems, increasing susceptibility to arrhythmias and sudden cardiac death. As a result, the authors suggest that it is beneficial to monitor heart rhythm in HD patients, even when there are no prior signs of heart disease.
The loss of grey matter in a brain region called the hypothalamus has been well-documented in HD, and is believed to contribute to circadian rhythm and habitual sleep disturbances.
In a January study published in the Journal of Neurological Sciences, a group of Australian and British scientists investigated the impact of multidisciplinary rehabilitation therapy on hypothalamic grey matter loss and circadian rhythm and habitual sleep disturbances in a group of individuals with preclinical HD. The nine month-long study found that a specialized rehabilitation therapy designed by a team of exercise scientists, cognitive training, sleep, and circadian rhythm specialists, neuroscientists, and a neuropsychiatrist was able to reduce hypothalamic grey matter volume loss. However, the scientists did not observe any significant changes in sleep disturbances.
The current COVID-19 (coronavirus) crisis presents with unprecedented challenges and uncertainties for all. In this article, we hope to contribute to increasing awareness and knowledge about COVID-19. While the information and resources provided below are by no means exhaustive, we hope that they can be helpful for HD patients and their caretakers.
COVID-19 General Info
COVID-19, which stands for coronavirus disease 2019, is a highly contagious viral infection caused by a newly identified virus called SARS-CoV-2. The World Health Organization (WHO) declared COVID-19 a global pandemic on March 11, 2020. While scientists are still researching the transmission of the virus, it is believed that COVID-19 is primarily spread among people through close contact and respiratory droplets. Symptoms can vary from person to person and start 2-14 days after exposure, but common symptoms include dry cough, shortness of breath/difficulty breathing, fever, chills, repeated shaking with chills, muscle pain, headache, sore throat, and new loss of taste or smell. According to the WHO, approximately 80% of people with COVID-19 recover without any need for special medical treatment, but 1 in 6 develop breathing difficulties and become seriously ill.
Click here to view the preventative measures described by the Centers for Disease Control and Prevention (CDC).
COVID-19 and Huntington’s
According to the European Huntington Association, Huntington’s disease itself does not necessarily put HD patients at a higher risk of contracting COVID-19. However, among HD patients that are symptomatic, there may be an increased risk of developing pneumonia as a result of being bedridden and undernourished. HD patients may also be at a higher risk of developing symptoms if exposed to COVID-19 and having a more serious illness.
Below are some potentially helpful resources for HD patients and their caregivers:
Virtual support groups and social support:
Other Helpful Resources:
A starter guide on how to navigate the popular video calling platform, Zoom
Device designed to help seniors connect with loved ones
Video calling app for android devices
A tool that crowdsources wait times for local stores and can be useful for avoiding crowds
By Maria Suarez-Nieto and Sepehr Asgari
On the 2nd of November, 2019, the Stanford University School of Medicine’s Huntington’s Disease Center of Excellence held their inaugural Stanford Huntington’s Disease Patient Care Symposium. Hosted in Mountain View, California, the event saw the participation of HD patients, caretakers, healthcare professionals, students, and members of the broader HD community. The symposium highlighted the latest advances in HD research from multiple perspectives, providing those in attendance with valuable new information.
The morning started with Daniel Jarosz, PhD and Assistant Professor of Chemical and Systems Biology and Developmental Biology at Stanford University, who dreams of the day when a treatment for HD exists. His informational talk focused on highlighting breakthroughs in basic science research for HD and other neurodegenerative diseases. Dr. Jarosz opened by explaining the work of Judith Frydman, who found that a chaperone protein, a type of protein that assists other proteins in carrying out their function, called TriC binds to the ends of Huntingtin protein fibers. This prevents the Huntingtin protein from aggregating, thereby suppressing the toxic effects of Huntingtin aggregation. Scientists further found that treating Hungtintin rich neurons with TriC helped normalize the structure of the protein. After explaining the methods used to discover that Huntingtin aggregates spreads between cells, Dr. Jarosz shifted his focus to explain how he used novel African turquoise killifish as a model for HD. Using that model, he identified that aged individuals have a strong enrichment in prion-like character among proteins known to form aggregates, meaning that aggregated proteins can spread similar to how prions do. If these findings are further confirmed, Dr. Jarosz stressed how this could be a new aspect of neurodegenerative disease behavior that we could potentially target.
Afterwards, Sharon Sha, MD, MS, Clinical Associate Professor of Neurology and Neurological Sciences at Stanford University and Co-Director of the Huntington’s Disease Center of Excellence and Ataxia Clinic, gave her talk on “Cognitive challenges in HD and ways to work around them.” Sha opened with an overview of symptoms commonly found in HD patients, which allowed her to introduce the main topic of her talk, cognitive symptoms. She deemed the cognitive impacts of HD “underrecognized,” and continued with explaining how these symptoms manifest in individuals, primarily by affecting their executive function, which could impact individuals years before motor impairments. Her research found that premanifest HD patients (patients in which symptoms have yet to arise) were more aware of presenting executive function problems than early stage HD. Sha proceeded to shift her focus to describing strategies that help treat cognitive problems, along with those that do not; she recommended using memory aids, decreasing multitasking, and being receptive to help. She continued by explaining that Donepezil, a drug commonly used to treat dementia in Alzheimer’s disease, does not work effectively to treat cognitive problems, along with the potential for another drug called Rivastigmine, and closed with addressed the prevalent insurance issues associated with clinical trials.
The third talk was given by John Barry, MD and professor of psychiatry and behavioral sciences at Stanford Medical Center, on the neuropsychiatric challenges that HD patients face. He opened with explaining how unawareness is hard-wired, not solely deniel. Barry described the disabling psychiatric symptoms often seen in HD patients, such as apathy, denial, depression, irritability, and anger among others; he emphasized that the disease, rather than the individual themselves, is the cause for these symptoms,.
After a short break, the morning resumed with a moving patient testimonial from Sheila A. She spoke about her own experience being diagnosed, and touched upon the guilt she felt at knowing it is possible that she passed HD down to her children, who were already born when it was discovered that HD is in her family. She explained the lack of resources available to her and her family living in Scotland at the time, along with her experience of her father being misdiagnosed. Sheila continued with her experiences in enrolling and participating in clinical trials that drove her to the US; despite not knowing what treatment group she belongs to, she is hopeful for the future of HD research and treatment, ending on the note that she finally felt “dignified in a really undignified disease”.
Following Sheila’s testimony was Kristina Cotter, PhD, who presented her dissertation research on “Positive attitudes and therapeutic misconception around clinical trials in the Huntington’s disease community.” Using a PACT-22 scale, which is a commonly used metric for clinical trial attitudes, her team developed a survey with two measures to assess clinical trial attitudes and understanding in the HD community. After distributing the survey via emails, flyers, and social media through HD-related organizations and evaluating 73 responses, Cotter and her team found that respondents viewed clinical trials positively and generally viewed trials as safe. She also explained that individuals with prior HD-related research experience were less likely to have negative expectations about trials than those without research experience, and that level of invasiveness was negatively correlated with willingness of an individual to participate. Interestingly, Cotter mentioned how she did not expect to find that individuals with HD were more likely than the other groups to experience therapeutic misconception; she concluded with recommending to use her findings to strengthen informed consent during HD clinical trial recruitment.
The last talk of the morning was a concise yet information-packed update on ongoing HD clinical trials by Brent Bluett, DO, clinical assistant professor in Neurology and the Neurological Sciences and Marcus Parrish, PhD of the Department of Chemical and Systems Biology. He touched briefly on a variety of ongoing drug-related clinical trials, shared contact information for audience members interested in such trials, and described how AMT-130 gene therapy has been found to lower huntingtin protein and improve HD symptoms in animal models. Bluett continued with emphasizing the ability to use of biomarkers as indicators of the severity and/or presence of HD, and concluded that biomarkers could be clinical trial endpoints for the HD community.
The afternoon began with an educational overview of nutrition, given by, Veronica Santini, MD, MA, and co-director of the Huntington’s Disease and Ataxia Clinic. She explained the higher total energy required for those with HD due to higher movement. She continued to explain healthy and unhealthy recommendations for HD patients; specifically, she mentioned decreasing lactose intake, while increasing the “colors” on a plate, particularly through vegetables.
The afternoon continued with a panel discussion about “Support Challenges in Huntington’s Disease” with social workers from the local community. Moderated by Dr. Sha and Dr. Santini, the panel consisted of Andrea Kahn, MS, CGC, Amee Jaiswal, LCSW, and Betsy Conlan, LCSW of Stanford Health care, among others. Each of these panelists introduced themselves gave attendees the opportunity to ask any questions they may have. They each provided expert answers for all questions from the audience members, which included those on along the topic of insurance protections, trust planning, pre-existing conditions under the Affordable Care Act, and long-term care. Panelists also recommended HD patients and families to enroll in a long term insurance plan prior to getting tested, mentioning the impact which positive results can have on the resources and coverage of an insurance plan.
The event concluded with a talk by Kristin Morris, PT, DPT, NCS, and physical therapist from the Stanford Neuroscience Health Center. She demonstrated examples of physical therapy style movements for those impacted by HD, and offered the opportunity for attendees to join in trying them out.
The first annual iteration of Stanford Patient Care and Research Symposium was a great success, bringing valuable information to and bringing together the HD community.