Genetics - predisposition to adult onset disease

Question 1

What are mechanisms of adult onset genetic disease?

Answer 1

Single gene
Chromosomal
Mitochondrial
Multifactorial - genes + environment

Question 2

What are clinical features of motor neurone disease/amyotrophic lateral sclerosis?

Answer 2

Progressive muscle weakness, wasting, and increased reflexes
Limb and bulbar muscles involved
Pure motor signs with fasciculations
Cognition spared
Death due to resp failure

Question 3

What is superoxide dismutase?

Answer 3

Catalyses conversion of intracellular superoxide radicals produced during normal metabolism

Question 4

What are the 3 types of superoxide dismutase?

Answer 4

SOD1 - located in cytoplasm
SOD2 - located in mitochondria
SOD3 - extracellular

Question 5

What is the purpose of SOD?

Answer 5

Protects cells from free radical damage leading to protection from:
Ageing and ischaemic tissue damage
DNA damage
Lipid peroxidation
Ionising radiation damage
Protein denaturation
Other forms of progressive cell degradation

Question 6

What type of genetic disorder causes Huntington’s?

Answer 6

Autosomal dominant

Question 7

What are motor features of Huntington’s?

Answer 7

Chorea
Athetosis
Myoclonus
Rigidity

Question 8

What are cognitive changes in Huntington’s?

Answer 8

Poor planning and memory
Subcortical dementia - executive function
NOT classical dementia

Question 9

What are personality changes in Huntington’s?

Answer 9

Irritable
Apathetic
Loss of empathy
Disinhibition
Self centred

Question 10

What psychiatric symptoms are in Huntington’s?

Answer 10

Depression
Paranoia
Psychosis

Question 11

What are advantages of predictive testing for Huntington’s?

Answer 11

Uncertainty of gene status removed
If negative, concerns about self and offspring reduced
If positive - Make plans for future, and inform children/decide whether to have children