History/Overview/Symptoms
What is Huntington's Disease?
It is an inherited disease that causes neurons in the brain to gradually breakdown and die.
What does CAG code for?
Glutamine (Q)
How many CAG repeats did the patient have?
28
At what age did the patient start to develop speech difficulties?
Seven years old
How many CAG repeats are needed for a Huntington's diagnosis?
36
In what year was Huntington's Disease discovered?
1872
What pattern of inheritance does Huntington's disease follow?
Autosomal dominant inheritance
What were the two main symptoms that the patient had?
Head bobbing and extremity tremors
What did the neurological exam show?
Dysarthria, cogwheel rigidity, hand tremor, and ataxia.
What tests do doctors perform in order to diagnose Huntington's disease?
Neurological exam, diagnostic imaging, and direct genetic test
In what age group is Huntington's Disease most prevalent?
In middle-aged people
In what areas of the brain do the mHTT proteins aggregate?
Basal ganglia and frontal lobe
What medication was the patient initially started on?
Tetrabenazine 12.5 mg, two times a day
What is the prevalance of Juvenile Huntington's disease?
0.7 per million patients per year
Are MRI's and CT scans always an accurate way of diagnosing Huntington's disease and why?
No because other disorders may also be causing the same CT or MRI results and Huntington's disease may not result in anything showing up on the MRI or CT.
Name three symptoms of Huntington's Disease.
Mild clumsiness, problems with balance or movement, cognitive or psychiatric problems, changes in behavior, chorea, akinesia, dystonia, temors, unusual eye movements, slurred speech, problems with swallowing, eating, speaking, and walking, weight loss, insomnia, loss of energy, fatigue, seizures
What is the mutation of the HTT gene called?
Trinucleotide repeat expansion mutation
What was the family history of the patient?
Sister that got diagnosed in her 40's, not other family history.
92 CAG repeats in HD allele 1 and 17 CAG repeats in HD allele 2
How many CAG repeats indicates no Huntington's disease?
26
When a patient with Huntington's Disease passes away, what is the cause of death? (Name one of the three)
Malnutrition, pneumonia, or heart failure
Explain genetic anticipation
Phenomenon in which the signs and symptoms of genetic conditions tend to become more severe and/or appear at an earlier age as the condition is passed from one generation to the next.
Possible answers: Caudate atrophy, severe neuronal loss in the basal ganglia, rare intraneuronal inclusions, Alzheimer type pathology
What did the MRI of the patient show?
Significant volume loss in the bilateral caudate heads associated with symmetric T2 hyperintensity in the putamen.
What is pre-genetic diagnostic testing?
Genetic modification that is used with In Vitro Fertilization (IVF) to make sure that any fertilized egg implanted does not have the abnormal gene