Huntington's disease is currently found in many different countries and ethnic groups around the world. The highest frequencies of HD are found in Europe and countries of European origin, such as the United States and Australia. The lowest documented frequencies of HD are found in Africa, China, Japan, and Finland.
Huntington disease affects an estimated 3 to 7 per 100,000 people of European ancestry. The disorder appears to be less common in some other populations, including people of Japanese, Chinese, and African descent.
o How many Australians have Huntington's disease? The best available published evidence of relevance to Australia suggests a prevalence rate of 8.4 per 100,000 people. This indicates that with a current population of 25.7 million people in Australia1, there is currently around 2,160 people with a diagnosis of HD.
Other countries where Huntington's is particularly prevalent include Ireland (10.6 per 100,000); Norway (6.7); Italy (6.35); Australia (6.3); Denmark (5.8); Great Britain (5.4); Slovenia (5.2); and Sweden (4.7).
Huntington disease (HD) results from CAG expansion in the huntingtin (HTT) gene. Although HD occurs worldwide, there are large geographic differences in its prevalence. The prevalence in populations derived from Europe is 10–100 times greater than in East Asia.
You're usually only at risk of developing it if one of your parents has or had it. Both men and women can get it. If a parent has the Huntington's disease gene, there's a: 1 in 2 (50%) chance of each of their children developing the condition – affected children are also able to pass the gene to any children they have.
The highest risk HD haplotypes (A1 and A2), are absent from the general and HD populations of Japan, and therefore provide an explanation for why HD prevalence is low in Japan. Such differences, therefore, suggest that the HTT allele originated independently in these three regions.
In the United States, Huntington's disease occurs in about one of every 10,000 to 20,000 people. It affects males and females equally and crosses all ethnic and racial boundaries. Typically, symptoms begin between age 30 and 55.
HD is caused by a mutation in the gene for a protein called huntingtin. The defect causes the building blocks of DNA called cytosine, adenine, and guanine (CAG) to repeat many more times than they normally do. Most people have fewer than 27 CAG repeats in their HD gene, so they are not at risk for the disease.
Nine patients have died, and seven have been lost to follow up. The range of disease duration was between 2 and 17 years, the oldest living to age 91.
Because Huntington's is a genetic disease, you can't do anything to prevent it if you have inherited it. If you have a history of Huntington's disease in your family, you may wish to have genetic counseling before having children of your own.
Conclusion The most primary cause of death in HD is aspiration pneumonia.
In around 3% of cases of Huntington's disease, there's no obvious family history of the condition. This could be because relatives with the condition died before they were diagnosed with it. In rare cases, it's due to a new fault in the gene that causes Huntington's disease.
Although no disease-modifying therapies currently exist to slow or halt the progression of Huntington's disease, many new types of treatment are under investigation that may offer hope for the future.
After Huntington's disease starts, a person's functional abilities gradually worsen over time. The rate of disease progression and duration varies. The time from the first symptoms to death is often about 10 to 30 years.
Huntington's disease does not skip generations. Each child of a parent with Huntington's has a 50% chance of inheriting the defective gene. If a child does not inherit the gene, he or she cannot pass it on. If the child does inherit the gene, he or she can pass it on and will develop the disease.
Symptoms of Huntington's disease usually develop between ages 30 and 50, but they can appear as early as age 2 or as late as 80. The hallmark symptom of Huntington's disease is uncontrolled movement of the arms, legs, head, face and upper body.
There have been reports that juvenile onset Huntington's chorea is almost always inherited from the father, and that late-onset Huntington's chorea is inherited more often from the mother than from the father.
Huntington's disease is inherited in an autosomal dominant fashion. The probability of each offspring inheriting an affected gene is 50%. Inheritance is independent of gender.
Hospice referrals for Huntington's can be challenging because it's difficult to predict decline. Common end-of-life signals include significant weight loss, difficulty swallowing or breathing, recurrent aspiration pneumonia, and uncontrolled pain.
There was evidence of an increasing prevalence of between 15 and 20% per decade in studies from Australia, North America and Western Europe.
The worldwide service-based prevalence of HD, based on a meta-analysis (n = 13 studies), was 2.71 per 100,000 (95% CI: 1.55-4.72). Eleven studies were conducted in Europe, North American, and Australia, with an overall prevalence of 5.70 per 100,000 (95% CI: 4.42-7.35).
Early symptoms of Huntington's disease (HD) include mood swings, depression and irritability. Patients may notice problems in their daily activities such as driving, learning new things, remembering a fact or making a decision.