Huntington 's Disease ( Hd ) Essay

1854 Words Mar 21st, 2016 8 Pages
Huntington’s disease (HD) is a late-onset, usually between 35 and 50 years old, neurodegenerative disorder prevalent in 3-7 per 100,000 people of European ancestry1. The disease, inherited in an autosomal dominant pattern2, is characterized by motor disturbance, intellectual decline, and psychiatric manifestations3. The disease is difficult to detect at an early stage of an individual’s life since its symptoms appear in the third to fifth decade of life. To better understand the disease, investigations were done to identify the gene that is linked with the disease. Some of the common approaches to do this was linkage analysis and positional cloning often involving the use of polymorphic DNA markers to identify the best candidate gene that can be linked to the HD.
The first study that established the linkage of a DNA marker to the HD gene was conducted by Gusella et al. in 1983. Taking advantage of the recombinant DNA technology, they used restriction fragment length polymorphisms (RFLPs) as DNA markers to determine linkage of the disease gene in large multigenerational families. The DNA of the affected individuals from two families of American and Venezuelan descent was analyzed using DNA probes. The latter, which were free of repetitive sequences, can detect RFLPs which were present in the regions of the genome. The researchers constructed a human genetic linkage map, thus, they were able to localize the genes that can give a suggestion of linkage to the disease. Their…

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