Huntington's disease

Peta Brennan just turned 31 years of age, but she played down her birthday, as usual. It felt too much like part of a countdown.

The dread of another passing year is something Ms Brennan shares with her cousin Katie Young, 30.

Both women are from the NSW Hunter region and both have Huntington's disease.

Their fathers are among a generation of five Brennan men to have the disease.

Three of the brothers including Ms Brennan's father, Mark, are now dead.

The remaining two, including Ms Young's father Stephen, face shortened, diminished lives in aged care.

"There's only two left. They all pass away. Within a year or two we lost all of them around the same time," said Ms Brennan, whose father died at 60…

Dr David Williams, a neurologist at Newcastle's John Hunter Hospital, said the deadly genetic disease caused a person's movements to become "ballistic" and jerky, and took a severe toll on their cognitive ability.

"If I set out to tell a story, there's a trajectory and I might try to land a punchline," Dr Williams said.

"They go on tangents all the time. They have difficulty following a thought."

Perhaps most distressing for carers of people with Huntington's, Dr Williams said, was their loved ones' psychotic disturbance.

Sufferers are often anxious, depressed, easy to anger, prone to misreading social situations and quick to react.

Most die within 20 years of being diagnosed.

It is a cycle familiar to the next generation of Brennans…

If you are born to a parent with Huntington's your chances of acquiring it are 50-50.

That seems a cruel statistic to the Brennans, who count at least 20 of their family members with the illness, and four without.

The family's running joke is "that Brennan luck, again".

"It's supposed to be 50-50, but our family is ridiculous," Ms Young said.

Her sister Emma, about a year younger, has also been diagnosed with Huntington's and is already showing more obvious symptoms.

It means Katie and Emma's mother, Angela Hiscock, has seen her husband Stephen live in a nursing home since the age of 45, and two of her three daughters inherit the illness.

For a short time in his late 50s, Stephen lived in the same home as his brother Mark.

"[Stephen is now] the youngest one [in the nursing home] by far, and it's just sad to see him in there with all these old biddies," Ms Young said.

Ms Brennan said her father was often bad-tempered in the final years of his life…

The decision to have herself tested for Huntington's, Ms Young said, came with a recommended course of counselling sessions.

But being told of her sister Emma's diagnosis, she said, was worse than hearing her own.

Now Katie and Peta watch Emma, knowing her present struggles might await either of them on the other side of the next birthday, or even by Christmas.

"For Emma it's mainly the anger at the moment, clumsiness, not being able to remember anything," Ms Young said.

"One day being so sad you can't get out of bed. Can't even put your makeup on anymore."…

There is no a cure for Huntington's but there is promise, Dr Williams said, in research using antisense therapy — which tackles genetic disorders or infections.

Huntington's is caused by a mutation in a single gene that makes a protein called huntingtin.

A clumping effect and increased 'stickiness' causes the brain cells of Huntington's sufferers to die.

A treatment used in international trials, Dr Williams said, has excited Huntington's sufferers with its potential to stop the mutant protein by silencing the mutated gene.

Clinical trials by British and US researchers in 2014 tested the safety of a drug in people for the first time.

It resulted in decreases in the level of huntingtin in the cerebrospinal fluid of the trial's participants, who were people in the early stages of Huntington's disease.

Those trials did not demonstrate that Huntington's disease could be treated, but the pharmaceutical company Roche of Basel, Switzerland, planned to run expanded trials this year.

The Brennan women know a cure might never arrive, but they are determined to be the last in their family with Huntington's.

Medical science has already allowed Ms Young to have two children and Ms Brennan is expecting her second.

The options of IVF and testing for the disease at 11 weeks in utero mean that someone with Huntington's can be certain their child will not have it.

"A lot of people decide not to have kids, so that was the hardest part of it," Ms Brennan said.

http://www.abc.net.au/news/2018-10-04/family-with-shockingly-high-rate-of-huntingtons-disease/10237180