Huntington Chorea – Genetic Developments, Coursework Example

Abstract

Huntington Chorea is an autosomal dominant progressive neurodegenerative disorder. The evolution is fatal in a range from ten to fifteen years. The gene malfunction is located on 4p16.3. Most HD patients carry expanded polyQ in huntingtin, the disease protein, in the range of thirty eight to fifity five glutamines and will develop the disease between thirty and fifty years of age. Other HD patients that have more than sixty repeats may have a juvenile onset. The standard Sanger sequencing  used nowadays to detect mutations that are causative or risk factors for neurodegenaratives disease including Huntigton´s is expensive and slow. New technologies are being developed to speed up the diagnosis. This paper explores real life situation in a genetic counselling of Huntigton Chorea. In conclusion it is crucial to inform the family about the disease, it´s evolution and treatments available. In my opinion, should avoid informing insurance health company or employers about Huntington Chorea before it sets in.

Keywords: Huntigton Chorea, genetical counselling

Huntington Chorea – Genetic Developments

Huntington chorea (HD) is an autosomal dominant progressive neurodegenerative disorder. It can start in fifth or sixth decades of life with a distinct phenotype characterized by chorea, dystonia, incoordination, cognitive decline and behavioral difficulties. The evolution is fatal in a range from ten to fifteen years. The gene malfunction is located on 4p16.3.

Literature review

The animal model discussed in a scientific article (Chang, Liu, Li, & Li, 2015) is based on recognized fact that most HD patients carry expanded polyQ in huntingtin, the disease protein, in the range of thirty eight to fifity five glutamines and will develop the disease between thirty and fifty years of age. Other HD patients that have more than sixty repeats may have a juvenile onset. Those repetitions are a part of DNA itself. There are two categories: the SINEs (short elements) and LINEs (long elements). One of the most relevant types of SINEs is the ALU repetition, present in almost 10% of all human DNA. Those ALU repetitions and LINEs are able to generate self-copies and insert in other parts of our genome. This insertion might interrupt a codifying gene and cause a genetic disorder (Jorde, 2010a).The usual risk factors related to genetic malformations or disorders might be medicines or drugs, environmental factors, radiations or genetic alterations (Jorde, 2010b).The genetic alterations are clearly identified in HD but scientists are looking for other risk factors to help speed up diagnosis before HD sets in.

According to a new research (Van Giau, An, Bagyinszky, & Kim, 2015), the standard Sanger sequencing  used nowadays to detect mutations that are causative or risk factors for neurodegenaratives disease including Huntigton´s is expensive and slow. They show in their work next generation sequencing strategies. According to the authors, this study could enhance disease diagnosis and would be also helpful in estimating the risk for disease onset in the future.

Conclusion

In genetic counseling, my conduct would be inform the family about the disease and the inheritance model, about diagnostic availability, keep this information under secret according to healthcare ethics, inform about its fatal progression. I would not inform healthcare insurance or company unless mandatory according to local legislation.

References

Chang, R., Liu, X., Li, S., & Li, X. J. (2015). Transgenic animal models for study of the pathogenesis of Huntington’s disease and therapy. Drug Des Devel Ther, 9, 2179-2188. doi: 10.2147/dddt.s58470

Jorde, L. B. (2010a). Genes and Genetics Diseases. In K. L. McCance & S. E. Huethe (Eds.), Pathophysiology: The biologic basis for disease for adults and children (6th ed., Vol. 1, pp. 126-157). St. Louis, Missoury: Mosby Elsevier.

Jorde, L. B. (2010b). Genes, Environment-Lifestyle and Common diseases. In K. L. McCance & S. E. Huethe (Eds.), Pathophysiology: The biologic basis for disease for adults and children (6th ed., Vol. 1, pp. 164-172). St. Louis Missouri: Mosby Elsevier.

Van Giau, V., An, S., Bagyinszky, E., & Kim, S. (2015). Gene panels and primers for next generation sequencing studies on neurodegenerative disorders. Molecular & Cellular Toxicology, 11(2), 89-143. doi: 10.1007/s13273-015-0011-9