Ricki Lewis

In honor of Rare Disease Day 2022, February 28th, I'm reposting a DNA Science story from nine years ago. February 16th was 12 years since Jane Mervar lost her young daughter to Huntington's disease (HD). Thank you

Jane for always sharing your story! (Updates are in parentheses.)

 

Looking back, signs that Jane Mervar's husband, Karl, had HD started when their youngest daughter, Karli, began to have trouble paying attention in school. Karl had become abusive, paranoid, and unemployable due to his drunken appearance. Karli, born in September 1996, was hyperactive and had difficulty following directions.

 

When by age 5 Karli's left side occasionally stiffened and her movements slowed, Jane began the diagnostic journey that would end with Karli's diagnosis of HD, which had affected her paternal grandmother.

 

Soon Karli could no longer skip, hop, or jump. New troubles emerged. "She had cold sweats, tachycardia, and chronic itching. She fell and suffered chronic pain. By age 6 she was losing her speech and became withdrawn," Jane recalls. Karli drooled and her speech became unintelligible. By age 7 her weight had plunged, and by age 8 she had developed pneumonia three times, due to difficulty swallowing. By age 9 she required a feeding tube, suffered seizures, and would go long periods without sleep.

 

An Adult's Disease in a Child

 

This isn't the way that a disease is supposed to run in families, striking child before parent. HD is regarded as a disease of adulthood, but in fact about 10 percent of people with the condition are under age 20 – they have juvenile Huntington's disease (JHD).

 

To continue reading, go to DNA Science, where this post first appeared. 

When results of a clinical trial of a treatment for a rare disease are disappointing, feelings of despair among hopeful affected families resurface – especially if the only options are repurposed drugs. That's the case for Huntington's disease, an inherited neurological condition that affects about 30,000 people in the US, 16 percent of them children.

 

The HD community is reeling from two such setbacks. But a new approach to halting the runaway expansion of the HD gene (called HTT) that lies behind the illness may reignite hope. The strategy focuses not on the HTT gene itself, but on another with which it interacts – a gene that takes part in repairing damaged DNA. Results appear in Cell Reports.

 

An "Expanding Repeat" Disease

 

"Horse-and-buggy doctor" George Sumner Huntington first described HD in 1872.

 

To continue reading, go to my DNA Science blog, where this post first appeared.

Last week's DNA Science post considered the ebb and flow of treatment possibilities for Alzheimer's disease. This week, it's Huntington's disease.

 

Like Alzheimer's, the less familiar HD also affects the brain, but HD is always inherited and is much rarer. The only treatments for HD manage symptoms, some of them prescribed off-label, borrowed from other conditions. A treatment that addresses the underlying cause of the disease, which delays onset or slows progression, has been elusive for decades.

 

A Disease Like No Other

 

HD is one of 40 "expanding repeat" diseases. A tiny part of a gene repeats many times, resulting in an encoded protein burdened with extra amino acids that interfere with its folding, rendering the protein sticky. In HD, mutant huntingtin protein gums up neurons in the brain's striatum, blocking signals essential to control movements and to think. Behavior changes too – anger and aggression may soar, as irritability, loss of impulse control, and confusion reign. The white matter part of the brain – the axons of those neurons – shrinks.

 

To continue reading, go to DNA Science, where this post first appeared.

I’m a big supporter of animal research, but I usually keep such studies out of my textbooks, because too many times what’s true for a mouse turns out not to be true for a person. But the news from Flav Giorgini and colleagues at the University of Leicester, University of Maryland School of Medicine, and Gladstone Institutes in San Francisco is hard to ignore – and it isn’t even in mice, but my old pals fruit flies.

The science is straightforward: blocking production of an enzyme called KMO, either by knocking out its gene or feeding flies drug-laced goop, enables flies with a version of Huntington’s disease to move more normally. HD is the neurodegenerative disease that struck Woody Guthrie, causing uncontrollable, dancelike movements. Dr. Giorgini discovered the connection to KMO in yeast in 2005, using resistance against cell death as a sign, since yeast are not known to dance. And the next step is obvious – try KMO inhibitors in people. The enzyme is also implicated in Alzheimer’s disease, ALS, AIDS dementia, and a host of other common conditions.

This fly/KMO study is a perfect example of the value of animal research. And so I went onto the People for the Ethical Treatment of Animals website to see what they had to say about the value of fruit fly research. Flies are, after all, animals. I found only an outdated blog comment about a PETA-provided bug catcher, which one would presumably use to escort errant cockroaches outside. The main page featured, as usual, the adorable – dogs, monkeys, and lions – and if you search a bit, the occasional mistreated turkey or lobster. The Bambi factor is at work - protect the furry.

I'm relieved. As a former Drosophila geneticist and author of fly porn, I personally murdered millions of the little beasts, heartlessly drowning them in vats of mineral oil, or exploding their innards when I drank too much coffee before injecting them. Since then, I've lived in fear of attack by Alicia Silverstone. I guess I can keep my American Physiological Society “I’m Alive! Thanks to Animal Research!” tee shirt. Read More