Living With Huntington’s
Molecular Biologist Cynthia McMurray:
Dismantling a DNA Destroyer
McMurray Hunts Disease
Molecular biologist Cynthia McMurray seeks the cause of a gene glitch
Targets the brain
Damages DNA in brain cells
Triggers death of brain cells
Do you carry the gene for Huntington’s?
Photo: Matt C. Meyer
Everyone carries the gene for Huntington’s
The Huntington’s gene is one of about 20,000 genes in the human genome
But only people with a slight glitch in the gene get Huntington’s
Huntington’s is highly heritable
Risk of having Huntington’s glitch: 1 in 10,000 in general population (1/10000th %)
Risk of having Huntington’s glitch if parent has disease: 50%
Facts About Huntington’s Disease
Huntington’s affects men and women, as well as all races and ethnicities
Symptoms usually appear in mid-life
Symptoms can include impaired movement, mood, speech, and memory
As disease progresses, symptoms worsen
There is no cure
Partial Gene Amplification: CAG
Cytosine, adenine, guanine (CAG) base sequence repeats over and over
Frequent CAG repeats are found in other brain diseases
People with Huntington’s have 37-80 CAG repeats
People without Huntington’s have about 36 or fewer CAG repeats
The Effects of DNA Damage
Hypothesis #1: Unstable DNA causes instability of motion, thoughts, and moods in Huntington’s disease
Discovery #1: CAG repeats form abnormal looplike structures on parts of DNA, thereby enabling even more CAG repeats
Next Question: What allows the looplike structures to become permanent?
Understanding DNA Damage
Reactive oxygen species (free radicals)
Normal DNA repair machinery
What role does McMurray believe these play in Huntington’s?
How is this affected in Huntington’s?
What possible roles might this lipid play in Huntington’s?
Genetic testing can determine if you are at risk for developing some diseases
Risk for about 1500 diseases can be identified
DNA from hair, saliva, or skin reveals if you have gene abnormalities
What are some of the ethical and emotional considerations associated with genetic testing for disease risk?