5.3 huntingtons Flashcards
sets of symptoms
motor
cognitive
emotional
psychosis
genetic level pathology of huntingtons
CAG region of HTT gene continually repeated, greater than the normal limit <25
molecular level pathology of huntingtons
Huntingtin protein formed is abnormally expanded, dysregulating cellular processes
the cellular processes that abnormal huntingtin protein disrupts 3
transcription
immune function
mitochondrial function
gross pathology from huntingtons
loss of medium spiny neurons and progressive atrophy of the striatum
affects indirect pathway of movement predominantly
how does the indirect pathway get affected in huntingtons and what relevant symptom does that link to
affects the neurons in the indircet pathway
results in loss of d2 receptors
hence the glutamate effect of the pathway is favoured
resulting in thalamus over-excitation
results in chorea
diagnosis of huntington
characteristic signs
positive family history
blood test for PCR to analyse number of CAG repeats
describe how disease occurrence can be classified according to range of alleles
Severity/liklihood of getting disease dependent on number of CAG repeats, there is a range in which above that known to get disease
normal repeat range
<25
pathogenic range
> 36 repeats
reduced penetrance HD causing alleles
36-39
some may never develop symptoms
asymptomatic in the elderly
full penetrance HD causing allele
> 40
people will develop symtpoms during their normal life span
anticipation in huntingtons
the disease gets more severe with earlier onset as passed on to the next generation, particularly if paternal inheritance
due to progressively less stable DNA
cis factor in huntingtons
this refers to severity of the disease.
the cis factor of huntington is where the CAG repeats are interrupted or not and if so how frequently.
the less interruptions the worse
symptoms of huntingtons
motor: chorea, loss of cordination, slurred speech
cognitive: memory decline, difficulty making decisions
emotional: apathy, aggression, personality changes, depression
psychosis: hallucinations, schizophrenia, bipolar disorder
