Although anyone can develop HD, it tends to run in people of European descent (having family members who came from Europe). But the main factor is whether you have a parent with HD. If you do, you have a 50% chance of also having the disease.
Each child of a parent with HD has a 50 percent chance of inheriting the HD gene. A child who does not inherit the HD gene will not develop the disease, and generally, they cannot pass it on to their children or other future generations.
Huntington's disease is caused by a faulty gene. Cells in parts of the brain are very sensitive to the effects of the faulty gene. This makes them function poorly and eventually die. A parent with the Huntington's disease gene has one good copy of the gene and one faulty copy.
It affects males and females equally and crosses all ethnic and racial boundaries. Typically, symptoms begin between age 30 and 55. Children of parents with Huntington's disease have a 50 percent chance of inheriting the HD gene.
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.
Early symptoms
The first symptoms of Huntington's disease often include: difficulty concentrating. memory lapses. depression – including low mood, a lack of interest in things, and feelings of hopelessness.
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.
An affected person usually inherits the altered gene from one affected parent. In rare cases, an individual with Huntington disease does not have a parent with the disorder. As the altered HTT gene is passed from one generation to the next, the size of the CAG trinucleotide repeat often increases in size.
“Some people in this range do get Huntington's while some live into their 90s and never get a symptom,” says Shealy. “That's one of the limitations of genetic testing. We can't always give you a yes or no answer.”
Lots of people at risk of Huntington's disease decide they'd rather not know until any symptoms appear. If you do want to know, ask your GP for a referral to a genetic counsellor. You'll have several appointments with the counsellor.
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.
Prevention of Huntington's disease
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.
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.
The future of Huntington's disease management
“The goal is to slow down the course of Huntington's disease, preferably preventing its progression entirely.” Younes indicated there might even be an opportunity to proactively start treatment for people who carry the genetic mutation that causes Huntington's disease.
From the onset of symptoms, people with HD have a life expectancy of 10 to 25 years. HD is not evident at birth. In fact, symptoms will usually not appear until a person is between 35 and 55 years of age, and occasionally even later in life.
There is no cure, and it is fatal. People are born with the defective gene that causes the disease. But symptoms usually don't appear until middle age. Most cases of Huntington's disease are diagnosed between the ages of 30 and 50.
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that usually starts in mid-adult life. The clinical disease progresses to death over an average of 20 years.
On neuroimaging atrophy of the corpus striatum involving the caudate and putamen is seen. This change generally proceeds from medial to lateral and dorsal to ventral. These changes are better appreciated on MRI than on CT.
Onset occurring ≤20 years is classified arbitrarily as juvenile-onset HD (JHD). The youngest symptomatic child documented had an age of onset of 18 months,3 with other children developing symptoms in their teens, meaning that some individuals with JHD may now be in their twenties.
Huntington's is a dominant genetic disease. With these diseases, you are almost never an invisible carrier like you can be with recessive genetic diseases. You usually can't pass on a gene that causes the disease because you don't have it.
Symptoms typically emerge from age 30 to 50, but also can develop in children and older adults. Late-onset Huntington's, characterized by some as emerging after age 5o and others after age 60, is thought to be less severe than earlier onset Huntington's.
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.
This disease often affects a person's ability to plan, make decisions, and process complex topics. But patients usually retain past memories, and are able to recognize people, objects, letters, numbers, and colors. They are often able to continue carrying out jobs that they have previously been doing for many years.
Huntington's disease is autosomal dominant, meaning inheritance of just a single copy of an abnormal chromosome from a biological parent is enough to cause it. If one parent carries the abnormal gene, each of their biological children has a 50 percent chance of Huntington's disease inheritance.