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Flashcards in Disease Deck (18)
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1

What theory explains how mitochondria came to be an intracellular organelle? What is a mitochondrias main role?

Endosymbiosis - mitochondria generate ATP for the cell

2

Which tissues would you expect to be more affected in mitochondrial disease? Why?

The heart, brain, and skeletal muscles etc - these tissues contain abundant mitochondria, as they require much more energy than other parts of the body

3

List some symptoms you may expect in mitochondrial disease.

- muscle weakness
- seizures
- developmental delays
- visual/hearing impairment
- learning disabilities
- poor growth

4

Regarding symptoms, why does the clinical presentation of mitochondrial diseases often cause difficulty in diagnosis?

Symptoms are often broad and varied, involving various organs with various severities - many of these symptoms are also universal to various other disorders

5

Symptoms of mitochondrial diseases can range from mild to severe. Why is this?

Mitochondria produce their own DNA - therefore, depending on the amount of mitochondria an individual posses which contain the mutation, an individual may experience severe symptoms (resulting from a majority of abnormal mitochondria) or mild symptoms (resulting from a minority of abnormal mitochondria)

6

What features of a family history would aid a doctor in identifying a possible inherited disorder?

Looking for mild symptoms, and/or sufferers, in previous generations

7

Mitochondrial diseases are inherited maternally. Does this mean they are X-linked?

No - mitochondrial DNA is not chromosomal, and is independent

8

Which ethnicity is sickle cell anaemia most commonly associated with?

Individuals of African origin

9

Describe specifically the mutation that leads to sickle cell anaemia.

Sickle cell anaemia is caused by a mutation from an A --> T in the Beta globin gene - this occurs in the amino acid at position 6, resulting in a glutamate to a valine substitution (missense mutation)

10

Is sickle cell anaemia a dominant or recessive disease?

Recessive

11

What is the sickle cell trait? What does it infer?

The sickle cell trait is seen in individuals who are heterozygous for the sickle cell allele and the wild type - this infers some resistance to specific forms of malaria

12

List some of the symptoms of Huntingtons disease.

- dementia
- seizures
- abnormal gait
- personality change

13

What mutation results in Huntingtons disease?

An expansion of a sequence of short tandem repeats (CAG) - in a healthy individual there are 10-26 repeats of glutamine - in an unhealthy individual, there are 38-80 repeats

14

What is the general age on onset of Huntington's disease?

Around 40-50

15

Is Huntington's disease autosomal dominant or recessive?

Autosomal dominant

16

Do we understand the function of the Huntington's gene? Does this matter clinically?

No - this doesn't matter wholly as we can still design treatment plans regardless

17

How may epigenetics help in treatment of sickle cell disease?

Turning on/off specific genes - turning off the BCL11A could give rise to the gene coding gamma globin as opposed to the abnormal beta globin

18

The blockage of which pathway has saved yeast from Huntington's disease? Which other model organisms was this shown in?

The kynurenine biochemical pathway - this has also been shown in drosophila and mice