Predisposition to Adult Onset Disease Flashcards
What are some mechanisms of adult onset genetic disease?
Single gene, chromosomal, mitochondrial and multifactorial
What is amyotrophic lateral sclerosis (motor neuron disease)?
Generally sporadic
Mean age onset 55 years
5-10% familial
What are the clinical features of amyotrophic lateral sclerosis?
Progressive muscle weakness, wasting and increased reflexes
Limb and bulbar muscles involved
Pure motor signs
Cognition spared
Death due to respiratory failure
Describe Cu/Zn superoxide dismutase (SOD) in amyotrophic lateral sclerosis
1y function - catalyses conversion of intracellular superoxide radicals produced during normal metabolism
Ubiquitous enzyme, motor neurons express it highly
What are the 3 forms of superoxide dismutase (SOD)?
SOD1 - located in cytoplasm
SOD2 - mitochondria
SOD3 - extracellular
What is contained in the genes SOD?
SOD1 and SOD3 have copper and zinc
SOD2 have manganese in reactive centre
Genes located on chromosomes 21, 6 and 4
What is the action of SOD?
Protects many types of cells from free radical damage that is important in ageing and ischaemic tissue damage
Helps protect cells from DMA damage, lipid peroxidation, ionising radiation damage and protein denaturation
What is the treatment for amyotrophic lateral sclerosis?
Incomplete penetrance
No cure or satisfactory treatment
What is Huntington’s Disease?
Autosomal dominant
Adult onset
Unique mutation identified
What are the clinical features of Huntington’s disease (HD)?
Movement disorder
Chorea, athetosis, myoclonus and rigidity
What are the cognitive changes of HD?
Poor planning and memory
Subcortical dementia
Not classical dementia
What are some personality changes of HD?
Irritable, apathetic, loss of empathy, disinhibition and self centered
What are the psychiatric aspects of HD?
Depression, paranoia and psychosis
When is the onset of HD?
Late 30s to early 40s but variable
15-20 years duration
Fully penetrant
What is the treatment for HD?
No cure and unsatisfactory treatments
