B2. Genetic Factors

Question 1

What is DNA?

Answer 1

t is a chemical made up of two long molecules, arranged in a spiral. We refer to this as the double-helix structure.

Question 2

Where is DNA found?

Answer 2

It is found in your chromosomes​
You have 23 pairs of chromosomes​
Each chromosome has Genes, which is made up of a sequence of DNA​
The Genes will determine your genetic makeup​

Question 3

What does DNA contain?

Answer 3

​DNA contains the instructions for making proteins. These proteins regulate the development of a human being

Question 4

What is a genetic predisposition?

Answer 4

A genetic predisposition is an increased likelihood of developing a particular disease based on a person’s genetic makeup.​

Question 5

Give some examples of Predisposition diseases?

Answer 5

Cystic Fibrosis
Brittle bone disease
Phenylketonuria (PKU)
Huntington’s disease
Kleinfelter Syndrome
Down Syndrome
Colour Blindness
Duchenne muscular dystrophy

Question 6

Give some examples of susceptible diseases?

Answer 6

Cancer ​
Diabetes
High blood cholesterol

Question 7

Give some examples of biological factors?

Answer 7

Foetal alcohol syndrome 
Maternal infections during pregnancy ​
Lifestyle choices during pregnancy ​
Diet during pregnancy 
Congenital defects

Question 8

Describe the CF gene

Answer 8

One in 25 people carry the CF gene. For someone to be born with CF, both parents must carry the faulty gene.

Question 9

What is PKU?

Answer 9

PKU is a rare genetic disorder that prevents a child from breaking down phenylalanine, an amino acid (a building block for protein) found in many foods such as milk, meat and eggs. In PKU, if the child eats foods containing phenylalanine there is a build-up of harmful substances in the body that damages brain development. ​

Question 10

Can PKU be cured?

Answer 10

The condition cannot be cured. All babies in the UK are screened at birth by a heel-prick blood test. If a high phenylalanine level is detected, treatment will be started immediately with a special diet and medication to prevent the build up of harmful substances. ​

Question 11

How does PKU impact life?

Answer 11

A baby born with undetected PKU would fail to meet developmental milestones and experience developmental delay as their brain became damaged. Untreated PKU would result in severe learning disability and the child’s death.​

Question 12

How is brittle bone disease inherited?

Answer 12

Brittle bone disease may be passed from a person’s parents, but it can also develop
from a genetic mutation.

Question 13

What is brittle bone disease?

Answer 13

a disorder causing fragile bones that break very easily

Children born with brittle bone disease are at high risk of fracturing or breaking their bones easily because their bones develop without the right amount or type of a protein called collagen.

Question 14

can brittle bone disease be cured

Answer 14

It is a lifelong disorder
Children with brittle bone disease can
often be helped through physiotherapy, assistive equipment and drug treatments to
help strengthen their bones.

Question 15

What is Huntington’s disease?

Answer 15

Huntington’s disease is an inherited neurodegenerative genetic disorder that causes progressive damage to certain nerve cells in the brain.

Question 16

When does Huntington’s disease develop?

Answer 16

Huntington’s disease can develop at any age but often starts between the ages of 35 and 55.

Question 17

How does Huntington’s disease affect life?

Answer 17

It can affect muscle coordination and cause mental decline and behavioural changes. The brain damage gets progressively worse over time, with perception, awareness, thinking and judgement (cognition) affected.

Question 18

What are the earliest signs of Huntington’s disease?

Answer 18

The earliest signs are hardly noticeable and may be missed or mistaken for other conditions, for example subtle changes in personality and mood swings, irritability, altered behaviour and fidgety movements.

Question 19

What happens as Huntington’s disease develops?

Answer 19

As the disease progresses, the features of the disease can include psychiatric problems, problems associated with feeding, communication and erratic behaviour.

Question 20

What happens during the later stages of Huntington’s disease?

Answer 20

During the later stages of the disease, movement, behaviour and cognitive abilities are affected and the individual becomes increasingly dependent on other people for care and support.​

Question 21

What is Kleinfelter Syndrome?

Answer 21

A genetic condition in which a male is born with an extra X-chromosome.

Question 22

How many boys will get Kleinfelter Syndrome?

Answer 22

It is estimated that around one in 600 boys will be born with this condition, sometimes referred to as XXY. The extra X chromosome is acquired after the baby is conceived

Question 23

What are the signs of Kleinfelter Syndrome in babies?

Answer 23

the baby is slow in reaching milestones such as sitting up, crawling and walking.
The baby may be born with undescended testicles. Poor muscle power, delayed communication and a passive personality

Question 24

What are the signs of Kleinfelter Syndrome in boys?

Answer 24

experience difficulty socialising and expressing their feelings which can impact on emotional development and lead to low self-confidence. ​

experience mild learning difficulties such as low attention span and difficulty with literacy skills, especially reading, writing and spelling

experience higher rates of dyslexia or dyspraxia

physical signs include low energy levels and extra growth spurts, particularly in the legs and widening of the hips

The testes do not increase in size and there may be a lack of testosterone leading to a flabby body, low muscle tone, a reduction in calcium in the bones, small firm testicles, a small penis and lack of body or facial hair

There may be difficulties with sex drive (libido) and fertility

Question 25

Is Kleinfelter Syndrome curable

Answer 25

There is no cure but there is treatment
Treatment is available for low testosterone levels. Most adult males with this syndrome are able to live independently and establish careers and relationships​

Question 26

What is down syndrome?

Answer 26

a genetic condition that occurs as a result of an extra chromosome (chromosome 21).

Question 27

How is Down’s Syndrome inherited?

Answer 27

Down syndrome is not inherited. It is simply the result of a one-off genetic ‘mistake’ in the sperm or egg. There is a higher risk of giving birth to a baby with Down syndrome for women 45 years and older (about 1 in 50). In comparison, a 20-year-old woman has a risk of one in 1500.

Question 28

Give some physical features of Down’s syndrome

Answer 28

Relatively short fingers and small hands and feet
Excessive flexibility
Short height
Small head
Flattened face

Question 29

How many people are affected by Down’s syndrome?

Answer 29

recent research estimates that 60,000 people in the UK have the condition.

Question 30

What is colour blindness?

Answer 30

A very rare condition in which an individual has no colour perception at all.

Colour vision deficiency, where individuals have difficulty in distinguishing between different colours, is commonly known as colour blindness.

Question 31

How many people does colour blindness affect?

Answer 31

It affects approximately 2.7 million people in Britain, about 4.5 per cent of the population, mostly men.

Question 32

How do you become colour blind?

Answer 32

For the majority of people, the condition is genetic. Inherited colour vision deficiency is a result of an abnormality in the retina (the light-sensitive layers of cells that line the back of the eye). Others will experience the condition as a result of other diseases such as diabetes and multiple sclerosis. The ageing process or a side effects of certain types of medication can also affect colour recognition.

Question 33

What is a genetic predisposition?

Answer 33

Inherited genes that determine physical growth, development, health and appearance.

Question 34

What is Susceptibility?

Answer 34

increased likelihood of acquiring a disease because of genetic make up.

Question 35

What is cancer?

Answer 35

Cancer is a cell disease that results in them becoming abnormal and then further dividing, making more abnormal cells.
Most cancers can be linked to the environment and life style choices.

Question 36

Why are some people more at risk of getting cancer?

Answer 36

Some people are more at risk because they have inherited gene faults that increase their risk. There are a number of cancers where a genetic link has been shown, including cancer of the breast, bowel, womb and kidney. For those with the faulty gene, getting cancer is not inevitable although an unhealthy lifestyle will increase the risk.