Huntington Disease (HD), also known as Huntington’s Disease or Huntington’s Chorea, is a hereditary genetic disorder that results in the death of brain cells causing neuropsychiatric changes, choreiform movements and cognitive disturbances [1]. The most common form of HD is called adult-onset Huntington disease which normally develops around the ages of 30 to 50 [2,3]. A less common form of HD is known as Juvenile Huntington Disease (JHD) which usually develops in childhood or adolescence. The intention of this essay is to give a broad outline of adult-onset HD and explain the background biology and inheritance pattern of this genetic disorder.
Huntington Disease is a progressive, neurodegenerative disorder that is inherited in an autosomal …show more content…
The earliest and most severe site of atrophy occurs in the neostriatum (see figure 3 [12]). Gross atrophy occurs in the caudate nucleus and putamen, and this atrophy is accompanied by selective neuronal loss and astrogliosis [1]. The progressive shrinkage of the striatum correlates with the severity and progression of the disease, with almost no striatal tissue present in very advanced stages of the HD [13]. A system was developed to grade the severity of HD using macroscopic and microscopic criteria, based on the extent of gross striatal pathology, neuronal loss and astrogliosis. The grading system, seen in figure 3 [12], contains five grades (0-4) which are designated in ascending order of …show more content…
Three categories of genetic testing are used to predict or diagnose HD: Pre-symptomatic (or predictive) testing, confirmatory testing, and prenatal testing [16]. Prenatal testing, through tests such as chorionic villi sampling (around weeks 10-11) and amniocentesis (at weeks 14-18) can be used to test the fetus for the abnormal gene and inform parents. Pre-symptomatic testing is used for those that are at risk of having HD, based on family history, but have not presented with any signs of the disease. Confirmatory, or diagnostic, testing is used for patients that present symptoms of Huntington disease, in order to confirm or rule out the diagnosis of HD. Diagnostic testing normally involves the analysis of family history with a genetic test to confirm the diagnosis. Genetic testing to predict or diagnose HD involves the analysis of DNA to determine the presence of the HD mutation by counting the number of CAG trinucleotide repeats within the HTT gene. Many ethical issues accompany the gene testing so protocols have been established to provide counselling and support to those that seek genetic
Huntington Disease is a progressive, neurodegenerative disorder that is inherited in an autosomal …show more content…
The earliest and most severe site of atrophy occurs in the neostriatum (see figure 3 [12]). Gross atrophy occurs in the caudate nucleus and putamen, and this atrophy is accompanied by selective neuronal loss and astrogliosis [1]. The progressive shrinkage of the striatum correlates with the severity and progression of the disease, with almost no striatal tissue present in very advanced stages of the HD [13]. A system was developed to grade the severity of HD using macroscopic and microscopic criteria, based on the extent of gross striatal pathology, neuronal loss and astrogliosis. The grading system, seen in figure 3 [12], contains five grades (0-4) which are designated in ascending order of …show more content…
Three categories of genetic testing are used to predict or diagnose HD: Pre-symptomatic (or predictive) testing, confirmatory testing, and prenatal testing [16]. Prenatal testing, through tests such as chorionic villi sampling (around weeks 10-11) and amniocentesis (at weeks 14-18) can be used to test the fetus for the abnormal gene and inform parents. Pre-symptomatic testing is used for those that are at risk of having HD, based on family history, but have not presented with any signs of the disease. Confirmatory, or diagnostic, testing is used for patients that present symptoms of Huntington disease, in order to confirm or rule out the diagnosis of HD. Diagnostic testing normally involves the analysis of family history with a genetic test to confirm the diagnosis. Genetic testing to predict or diagnose HD involves the analysis of DNA to determine the presence of the HD mutation by counting the number of CAG trinucleotide repeats within the HTT gene. Many ethical issues accompany the gene testing so protocols have been established to provide counselling and support to those that seek genetic