Huntington’s Disease

1. Huntington’s Disease Kate Leary

2. Causes • Only caused by: • Inherited genetic defect • Mutation • Defect or mutation is a CAG repeat in the HD gene of chromosome 4 • CAG repeat  abnormal Huntingtin protein synthesized • Abnormal Huntingtin protein leads to premature death of nerve cells

3. Symptoms • Nervous System • Emotional • Physical • Immune System • Digestive System • Accidents • Death

4. Nervous System – Emotional • Stubbornness and frustration • Mood swings/changes • Unorganized • Difficulty concentrating • Loss of motivation • Loss of ability to interact • Perceived laziness puts stress on relationships • Depression

5. Nervous System - Physical • Premature death of nerve cells • Loss of short-term memory • Clumsiness • Stumbling • Difficulty walking • Uncontrollable muscle movements • Difficulty with speech • Difficulty swallowing • Less able to sit/stand stably

6. Immune System • Uncontrollable muscle movements lead to difficulty swallowing • Weight loss and lack of nutrients as a result • Weakened immune system • PRONE TO INFECTION

7. Digestive System • Difficulty swallowing from uncontrollable muscle movements • Weight loss • Lack of nutrients • Choking

8. Accidents • Uncontrollable muscle movements lead to: • Falling • Self-injury • Unable to take care of oneself

9. Death • Depression may lead to suicide • Death can also be cause by: • Falling • Infection • Self-injury • Choking ** Falling and infection are the most common causes of death in Huntington’s Disease.

10. Treatment Huntington’s disease is incurable, but you can treat some symptoms. • Medication • Movement • Mental • Therapy • Speech • Physical • Psycho

11. Medication • Movement disorders • Tetrabenazine • Help suppress involuntary movement • Antipsychotic drugs (Haldol &Clozaril) • Side effect of suppressing movements • Psychiatric disorders • Antidepressants (Lexapro, Prozac, Sarafem, & Zoloft) • Antipsychotic drugs • Suppress violent outbursts • Mood-stabilizing drugs • Prevent highs and lows associated with bipolar disorder

12. Therapy • Psychotherapy • Talk therapy to help with behavioral issues and learn coping mechanisms • Physical therapy • Help strength, flexibility, balance and coordination to reduce falls • Speech therapy • Strengthen muscles associated with speech, swallowing, and eating

13. Nutrition • Difficulty swallowing = weight loss • Lots of food and often • 3 large meals OR • Many snacks throughout the day • Eat a healthy, well-balanced diet BUT calorie rich • Soften/blend everything to make swallowing less difficult • Do not drink large amounts of liquids during meals to prevent a fake “full feeling” • Take time eating and sit comfortably

14. Physiology • # of CAG repeats on chromosome 4 • 11-34 = Normal • 37-121 = Huntington’s Disease • Too many repeats lead to production of abnormal Huntingtin protein • Function of Huntingtin protein not known yet • But function does affect basal ganglia • Basal ganglia • Control over movement of body

15. Physiology Continued • GABA neurons in basal ganglia • Produce GABA neurotrans- mitters (inhibitors) • Stop some “messages” from travelling through basal ganglia • Huntington’s Disease GABA function • Putamen's inhibitory GABA neurons are destroyed • Lead to disinhibition of thalamus and brainstem • Disinhibition = random, frequent motion

16. Physiology Continued • Putamen • Part of basal ganglia • Helps control movement of body • Projection to SNpc(substantianigrapars compacta) is necessary for movement

17. Physiology Continued • Huntington’s Disease Putamen • Projection to SNpc destroyed due to abnormal Huntingtin protein • Increased firing of dopamine neurons • Leads to disinhibition of thalamus and brainstem

18. Bibliography Board, A.D.A.M. Editorial. "Causes, Incidence, and Risk Factors." Huntington's Disease. U.S. National Library of Medicine, 18 Nov. 0000. Web. 06 June 2012. <http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001775/>. "Cause of Huntington's Disease." EMedTV. Clinaero. Web. 6 June 2012. <http://nervous-system.emedtv.com/huntington's-disease/cause-of-huntington's-disease.html>. "Effects of Huntington's Disease." What Are the Effects of Huntingtons Disease? Neurological Physiotherapy & Rehabilitation Physiotherapists. Manchester NeuroPhysio. Web. 06 June 2012. <http://www.manchesterneurophysio.co.uk/huntingtons/effects.html>. "Genetics and Physiology of Huntington's Disease." Macalester College. Macalester College. Web. 6 June 2012. <http://www.macalester.edu/psychology/whathap/UBNRP/Huntington/neuro.html>. "Huntington's Disease and Diet." Huntington's Disease and Diet. N.p., n.d. Web. 11 June 2012. <http://huntingtondisease.tripod.com/swallowing/id43.html>. "Huntington Disease." Huntington Disease. WebMD. Web. 06 June 2012. <http://emedicine.medscape.com/article/1150165-overview>. "Huntington's Disease (HD) - Pathophysiology." Huntington's Disease (HD) - Pathophysiology. Web. 06 June 2012. <http://www.mdvu.org/library/disease/hd/hd_path.asp>. Nordqvist, Christian. "What Is Huntington's Disease? What Causes Huntington's Disease?" Medical News Today. MediLexicon International, 02 Aug. 2009. Web. 06 June 2012. <http://www.medicalnewstoday.com/articles/159552.php>. Staff, Mayo Clinic. "Definition." Mayo Clinic. Mayo Foundation for Medical Education and Research, 05 May 2011. Web. 06 June 2012. <http://www.mayoclinic.com/health/huntingtons-disease/ds00401/dsection=treatments-and-drugs>. "Huntington Disease." Huntington Disease. WebMD. Web. 06 June 2012. <http://emedicine.medscape.com/article/1150165-overview>.

19. Questions • In which chromosome does the Huntington’s Disease causing CAG repeat occur? • What are the most common causes of death in Huntington’s Disease? • What are three types of therapy effective in treating Huntington’s Disease?