This paper examines Huntington's disease—a hereditary neurodegenerative disorder first described by George Huntington in the late 1800s—with a focus on its effects on oral histology, embryology, and the human immune system. The paper discusses how the disease's genetic basis, involving expansion of the CAG40 sequence, contributes to cognitive and motor impairments that degrade oral hygiene. It also explores the pathogenesis of associated dental conditions such as gingivitis, periodontitis, and bruxism, as well as the role of immune system overactivity in the disease's onset. Finally, it outlines practical oral care recommendations for patients and caregivers.
Huntington's disease is one of many neurodegenerative diseases, with chorea as one of its most prevalent symptoms (Hergert, Sanchez-Ramos, & Cimino, 2019, p. 1). Discovered in the late 1800s by George Huntington, a young American medical doctor at the time, the disease has gathered considerable interest from the medical community — though with little progress toward a cure. The disease is highly hereditary, with a 50% chance of transmission from parent to offspring (Boyle, Frölander & Manley, 2008, p. 333; Roos, 2010, p. 6). This hereditary property is due to the disease being a genetic disorder that is activated in those who exhibit its symptoms.
Importantly, every person carries the gene associated with Huntington's disease, and activation is equally likely across both biological sexes; however, those who develop the disease possess an expanded version of the gene. For individuals with this defective gene, onset typically occurs between the ages of 30 and 40; however, using medical imaging techniques, its manifestation can be predicted up to 15 years before onset (Petersén & Weydt, 2019, p. 179). Given the severity of this disease and its accompanying effects, patients typically die of either pneumonia or suicide (Roos, 2010, p. 2). This paper examines the consequences of Huntington's disease on oral histology and embryology, and also explores its pathogenesis and effects on the human immune system.
Oral histology and embryology describe the entire history of a person's dentition, from initial formation through the full lifecycle. Histology provides an account of tissue formation, development, and structure. In terms of oral health, this knowledge is important for understanding how the various components of the teeth are structured. Based on the genetic markers of Huntington's disease, its aetiology is not linked to the formations or structural developments found in a patient's oral histology or embryology. However, it does degrade the dental health of affected patients.
The most evident effect is due to impairment in the patient's cognitive, motor, and mental skills (Manley et al., 2012, p. 56). This significantly reduces their capacity to maintain healthy and clean oral tissues (Saft, Andrich, Müller, Becker, & Jackowski, 2013, p. 2). Other effects of Huntington's disease on dental health include decayed teeth, damage to posterior teeth, and slow or poor restoration of damaged dental tissues (Manley et al., 2012, p. 56). Huntington's disease therefore has a clear negative impact on oral histology and oral health. Notably, the treatment drugs used for the disease also carry side effects that degrade the oral cavity, though this can be mitigated through patient-specific diagnosis and treatment plans.
It is important to distinguish that, while Huntington's disease is present in its patients from birth, it is not a congenital disease. This distinction rests on the definition of congenital diseases as those that "manifest" or are "evident" at birth. In the case of Huntington's disease, manifestation is dependent on the continued expansion and repetition of the CAG40 genetic sequence. As the disease progresses, its negative effect on oral hygiene is largely due to orofacial dyskinesia and xerostomia. No significant markers indicate a direct degradation of dental tissues as a direct consequence of the disease itself (Boyle, Frölander & Manley, 2008, p. 335).
However, the accumulation of dental plaque, which leads to gingivitis, can further progress to periodontitis (Saft et al., 2013, p. 3). If periodontitis sets in, the periodontium becomes damaged and pockets begin to develop, with tooth decay and potential tooth loss as the direct consequences. Bruxism has also been found to affect dental hygiene in some patients with Huntington's disease (Manley et al., 2012, p. 60), and it follows from an escalated form of orofacial dyskinesia. Gingivitis — an inflammation of the gums — has been hypothesized to initiate and advance the progression of Huntington's disease (Rodríguez & Sánchez, 2015). While this remains inconclusive, its validity points to the potential for a deeper understanding of the disease's aetiology.
"Immune overactivity and cytokine involvement"
Currently, there is no cure for Huntington's disease. Medical researchers are consistently working on potential solutions for delaying the activation of the aberrant gene or targeting its replication. However, possible approaches to managing poor oral hygiene associated with the disease include: educating both patients and their caregivers on the importance of good oral hygiene to the overall condition; intentional oral care by attached caregivers; avoidance of gum disease and inflammation through a specialized dietary regimen; and, importantly, acceptance of assistance by patients themselves.
The use of dental floss and electric toothbrushes is also recommended for patients who are able to manage their own care, and the use of specialized toothpastes rich in fluoride is advised. Finally, every care team supporting patients with Huntington's disease should include a dentist to ensure excellent ongoing oral hygiene for such patients.
Boyle, C. A., Frölander, C., & Manley, G. (2008). Providing dental care for patients with Huntington's disease. Dental Update, 35(5), 333–336. doi:10.12968/denu.2008.35.5.333
Hergert, D. C., Sanchez-Ramos, J., & Cimino, C. R. (2019). Awareness of chorea in Huntington's disease. Journal of Huntington's Disease, 1–5. doi:10.3233/jhd-190381
Manley, G., Lane, H., Carlsson, A., Ahlborg, B., Mårtensson, Å., Nilsson, M. B., … Rae, D. (2012). Guideline for oral healthcare of adults with Huntington's disease. Neurodegenerative Disease Management, 2(1), 55–65. doi:10.2217/nmt.11.68
McColgan, P., & Tabrizi, S. J. (2017). Huntington's disease: a clinical review. European Journal of Neurology, 25(1), 24–34. doi:10.1111/ene.13413
Petersén, Å., & Weydt, P. (2019). The psychopharmacology of Huntington disease. Handbook of Clinical Neurology, 165(3), 179–189. doi:10.1016/b978-0-444-64012-3.00010-1
Rodríguez, M. L., & Sánchez, V. E. (2015). Periodontitis determining the onset and progression of Huntington's disease: review of the literature. Medwave, 15(9). doi:10.5867/medwave.2015.09.6293
Roos, R. A. C. (2010). Huntington's disease: a clinical review. Orphanet Journal of Rare Diseases, 5(1), 40–48. doi:10.1186/1750-1172-5-40
Saft, C., Andrich, J. E., Müller, T., Becker, J., & Jackowski, J. (2013). Oral and dental health in Huntington's disease — an observational study. BMC Neurology, 13(1), 2–5. doi:10.1186/1471-2377-13-114
You’re 88% through this paper. Sign up to read the remaining 1 section.
Sign Up Now — Instant Access Already a member? Log inAlways verify citation format against your institution’s current style guide requirements.