January 13, 2006

Drug helps runner stand up to disorder

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Megan Kenny overcame a severe blood pressure disorder to run in a marathon last year.

Drug helps runner stand up to disorder

Megan Kenny is something of a medical marvel. She has a disorder that usually causes such a severe drop in blood pressure when patients stand that they are unable to remain standing for more than a minute or two without losing consciousness.

Somehow during childhood, though, Kenny learned to cope. She bent forward or sat down and pretended to tie her shoes a lot, she said. Though she managed to be active, she couldn't run for more than a few seconds without having to sit or lie down.

Last year, after one year of treatment with the drug droxydopa — a treatment discovered at Vanderbilt University Medical Center — she completed the New Orleans Marathon.

Her remarkable feat is detailed in a case report in a recent issue of the British medical journal The Lancet.

“Ms. Kenny was of interest to The Lancet for both her determination and for the dramatic response to the droxydopa treatment,” said David Robertson, M.D., Elton Yates Professor of Autonomic Disorders and lead author of the report.

Kenny, 28, was diagnosed six years ago with complete dopamine beta-hydroxylase deficiency, a genetic condition she shares with one of her two brothers.

Dopamine beta-hydroxylase is an enzyme responsible for the synthesis of norepinephrine, an important neurotransmitter and regulator of blood pressure. Robertson and colleagues first described dopamine beta-hydroxylase deficiency 20 years ago, based on the first patient's blood biochemistry. On the night they discovered the disorder, they sat down and designed a drug treatment, Robertson said.

“It took a long time to make this drug droxydopa available to patients, but now we have a plentiful supply.” Droxydopa was the first drug that could replace an absent neurotransmitter in a human genetic disorder.

Complete dopamine beta-hydroxylase deficiency is a rare disorder, affecting only 20 individuals in the world, Robertson said. It shares orthostatic hypotension — low blood pressure on standing — with other autonomic nervous system disorders. Droxydopa can be used for any form of orthostatic hypotension.

“It may not always be the best drug for other forms (of autonomic disorders), but it is magic for dopamine beta-hydroxylase deficiency,” Robertson said.

Kenny said the treatment is “amazing,” though she is quick to point out that droxydopa hasn't completely changed her life.

“Growing up, my parents always encouraged me to be active, and I was. I haven't changed my interests. What the drug has done is really enhance what I'm able to do. I don't have to tie my shoes as often,” she said, laughing.

Kenny's tale should bring hope to those diagnosed with autonomic nervous system disorders, Robertson said.

“Megan Kenny's experience reminds us that the right drug in a person with determination and a positive outlook can work miracles.”