Psychiatry & Genetics

Question 1

What is the chance that a patient with Huntingtons will give it to their child?

Answer 1

50% chance

Question 2

What is meant by genetic “anticipation”?

Answer 2

Each generation develops the genetic disease at an earlier age

Question 3

What psychiatric symptoms can present in Huntington’s disease (potentially before physical signs of disease)?

Answer 3

Depressions
Compulsions
Anxiety
Suicidal Ideation
Blunted Affect
Psychosis

Question 4

What cognitive problems often appear in Huntingtons disease?

Answer 4

Decline in executive function (planning, abstract thinking initiating and stopping action etc)

Short and long term memory deficits

Dementia => progressive decline in global cognition

Question 5

What motor symptoms usually indicate Huntington’s disease?

Answer 5

• Choreiform movements
• Writhing movements
• Gait disturbance
• Rigidity
• Problems chewing/ swallowing/ speaking
• *All actions requiring muscle control = impaired**

Question 6

What protein is encoded in excess by the CAG trinucleotide repeat in Huntington’s disease?

Answer 6

Glutamine is overproduced

Question 7

What does overproduction of glutamine in Huntington’s disease cause?

Answer 7

Causes Huntingtin protein to crystallise out in neuron cell

=> neuronal cell death

Question 8

Transmission from what gender causes genetic anticipation in huntington’s disease?

Answer 8

Transmission FROM a MALE

• causes anticipation => increase in no. of CAG repeats and decrease in age of disease onset
• due to meiosis

Question 9

What are the reasons for and against genetic testing for Huntington’s disease?

Answer 9

FOR:

• family planning
• future planning e.g. power of attorney/finances
• awareness/mental preparation
• life insurance/ critical illness cover
• Anxiety of not knowing
• access to resources/benefits

AGAINST:

• knowledge of having disease causes anxiety for patient or family
• lack of curative treatment

Question 10

How are new treatments for Huntington’s disease attempting to reduce the amount of glutamine and slow progression of the disease?

Answer 10

• DNA makes RNA then RNA makes the protein
• intrathecal RNA analogue can be given to suppress the change from RNA to protein

=> Less glutamine produced but it does NOT cure the disease

Question 11

What patients are the most appropriate for the new mode of Huntington’s treatment?

Answer 11

Will benefit those who are pre-symptomatic most

Will not benefit patients who are already bedridden/dependent

Question 12

What are the prominent symptoms of Alzheimer’s dementia?

Answer 12

• Poor short term memory => learning new things = difficult
• Episodic memory => remember things happening a long time ago
• Can carry out tasks already well-practised
• dysphasia, dyspraxia, agnosia (difficulty recognising people)
• Mood symptoms illness

Question 13

What is the average life expectancy in ALzheimer’s after patients have a diagnosis?

Answer 13

average 7 years after diagnosis.

Question 14

When would a scan NOT be required for a diagnosis of Alzheimers?

Answer 14

If patient is old

OR typical presentation

Question 15

What would be found on a scan of a patient with Alzheimers dementia?

Answer 15

Mediotemporal lobe atrophy - Hippocampus shrinks

Cerebral atrophy - causing ventricles to appear bigger

Question 16

What part of a family history of Alzheimers would indicate an increased genetic risk?

Answer 16

Members of family affected by the disease at a younger age

Question 17

Frontotemporal dementia has a larger genetic component. TRUE/FALSE?

Answer 17

TRUE

Question 18

If a patient presents with dementia under the age of 60 is it more likely to be genetic?

Answer 18

All dementia is multifactorial BUT the genes which play a part are likely to have high penetrance

Question 19

How can patients with population risk or even an increased multifactorial risk modify their environment to prevent the onset of dementia?

Answer 19

Control environmental factors

e.g. smoking, diet, vascular risk factors

Question 20

What is the normal population lifetime risk of developing Alzheimer’s disease?

Answer 20

10%

Question 21

If a first degree relative has alzheimers, does this increase a patients risk from the population’s lifetime risk?

Answer 21

Increases it to 25%

Question 22

What percentages of the UK population are affected by Bipolar 1 and Bipolar 2?

Answer 22

1% - Bipolar 1

1-2% - Bipolar 2

Question 23

Hypomanic patients always have a disturbed sleep pattern. TRUE/FALSE?

Answer 23

FALSE

Hypomanic patients often sleep normally, however sleep is always affected in Mania

Question 24

What may cause patients to have a normal sleep pattern even during mania?

Answer 24

Use of medication - e.g. mood stabilisers, benzodiazepines, zopiclone etc

Question 25

Bipolar disorder can often appear as if it is Autosomal Dominant on Family trees. TRUE/FALSE?

Answer 25

TRUE

- modern family trees most likely to appear as if any mental health disorder appears in every generation (=> AD)

Question 26

Although bipolar disorder appears as Autosomal dominant on family trees, no gene link has been identified. TRUE/FALSE?

Answer 26

TRUE

- not known which gene to test

Question 27

Genetic testing is not completed routinely for bipolar disorder, but why could it be useful?

Answer 27

• Use of lithium straight away even if patient is only having depressive episode (as this will confirm bipolar)
• Use of mood stabilisers instead of antidepressants