Melissa Darnall could easily look around her family reunions and pick out who had Huntington’s disease (HD). The genetic disorder had affected four of her five aunts and uncles and her father, and the balance problems and shakiness typical of HD were readily apparent in those siblings.
Huntington’s disease is a neurodegenerative disorder characterized by poor muscle coordination, cognitive decline and psychiatric issues, typically with a middle age onset. Though it is rare in the general population, affected parents have a 50 percent chance of passing the disease on to their children.
Darnall was 22 when she took her father in after noticing his disheveled appearance and angry outbursts. He started believing there was a mold or poison in the house that was choking him, and resorted to sleeping in the car.
“He would leave the stove on and do other crazy stuff and I was so worried to go to work,” Darnall recalled. “We finally got him to the doctor and got him on an antipsychotic medication and he was fine.”
They suspected Huntington’s disease and genetic testing confirmed the diagnosis. As Darnall watched the disease symptoms take hold in her family members, typically around age 45, she decided she would never have children.
“That’s the only way to stop it from going to the next generation. I always pictured myself having children, but I don’t regret the decision at all,” said Darnall, who tested negative in 2010.
“My goal for my family has been to talk about HD, to stop hiding it and walking on eggshells. It’s a horrible thing, but there is support and people who do care.”
Drawing on her personal experience with the disease, Darnall serves as an HD advocate for Vanderbilt University Medical Center’s Huntington’s Disease Clinic, held the first Monday afternoon of each month. Though there is no cure for HD, the multi-disciplinary clinic offers a range of options to manage symptoms and many resources to help with the social side effects.
“Unfortunately, a lot of people don’t even understand what the disease is,” said Daniel Claassen, M.D., assistant professor of Neurology. “I really would emphasize that HD is a tragic disease. People at the prime of their lives are literally cut down. Every faculty is affected — cognition, mood, movement.”
Huntington’s disease occurs when the genetic code has too many repeats of the sequence CAG.
“If you make a chocolate chip cookie and you put in too many chocolate chips, the cookie will crumble. That’s the way it is with a CAG repeat. If you have too many of these, usually greater than 39, you’ll have dysfunction,” Claassen explained.
Often the first subtle sign of HD is difficulty with executive brain functioning, like multi-tasking or following the steps in a procedure. Movement symptoms manifest as unsteady gait or jerkiness and progress to involuntary motions called chorea, from the Greek root for “dance.” Patients may also have mood disorders, like depression or anxiety, make impulsive decisions or have bouts of irritability or rage.
With the cognitive problems and emotional outbursts, it is often difficult for HD patients to remain employed and many alienate their family and friends.
“In 25 years, these are the hardest cases I’ve ever seen,” said social worker Carol Rabideau, LCSW. “The patients can become combative with family members and sometime end up homeless if their behavior becomes unmanageable. Or, patients lose their job and their insurance, making it difficult or impossible to access health care or pay for medications.”
The first step for patients is often genetic counseling with a specialized protocol to help patients think through the implications of a diagnosis. Claassen or Peter Hedera, M.D., associate professor of Neurology, will then review family and medical history and evaluate any symptoms.
Patients having cognitive problems may see a neuropsychologist for further testing, those with a mood disorder will be prescribed medication, and those falling often will see a physical therapist.
Rabideau is on hand to help patients who may need to apply for disability or have trouble paying for medications, and Darnall provides information on support groups and other resources.
“The nice thing about this clinic is it’s not one standardized pathway. You don’t go through the checkboxes. We tailor it to each person. Lauren Griffin, our research analyst, will call each patient a week before they come in to go over the things we need to accomplish and organize the visit around those needs,” Claassen said.
Though today’s HD treatments are palliative, Claassen says there are exciting research studies on the horizon that could offer a cure.
“I think in the next five years, HD will have several really important clinical trials come up. Having a clinic where we concentrate our care in HD allows us to be involved in those trials and offers patients some hope and an opportunity to get involved in fighting the disease,” he said.
Many Vanderbilt researchers are investigating different aspects of HD, including Aaron Bowman, Ph.D., assistant professor of Neurology, who is working to understand why the disease presents at different times in different people. Research analyst Lauren Griffin is creating a repository of patient data with results from various questionnaires and cognitive assessments to use in future studies.
The HD clinic, which started in January, is now following 100 patients from Tennessee and parts of southern Indiana, western Kentucky and northern Alabama.
“HD is so unknown that when patients come here and find people who want to help and have resources, it’s a huge load off them. We have community resources and medical care available, and it’s one place they can come and get everything,” said case manager Jessica Stroh, R.N.
Stroh said “the icing on the cake” is having Darnall on hand to talk with patients.
“Without Melissa, we’re just another doctor’s office with pamphlets. When Melissa talks, we all listen. She has been through it all and has a perspective we can’t do without,” Stroh said.
Darnall said she simply finds joy in helping others. She helped form an affiliate group of the Huntington’s Disease Society of America and runs a monthly support group.
She also makes herself available anytime for questions and offers an “email buddy” for people uncomfortable with a public support group.
“It’s just talking with people, telling them you are not alone and even with this disease you can be a productive member of society and do all the things you want to do.”
