6. SICKLE CELL DISEASE Flashcards
1
Q
- What kind of disease is Sickle Cell Disease?
A
- it is a type of Autosomal Recessive Disorder
2
Q
- What is the statistic for the amount of people affected by Sickle Cell Disease?
A
- 1 out of every 400 African Americans
- 10% of African Americans have the Sickle Cell Trait
(allele) - the disease is also very prevalent in sub-tropical
regions
3
Q
- What causes Sickle Cell Disease?
A
- it is caused by the substitution of a single amino acid
- Glutamine is substituted for Valim
- this happens in the Haemoglobin protein
- this happens in red blood cells
4
Q
- What are 4 symptoms of Sickle Cell Disease?
A
- Physical Weakness
- Pain
- Organ Damage
- Paralysis
5
Q
- How can Sickle Cell Disease be treated?
A
- blood transfusions every 2 weeks
6
Q
- What can be said about Heterozygotes of Sickle Cell Disease?
A
- they are carriers of the Sickle Cell Disease allele
- it is not present in their phenotype
- they are usually healthy
- they can suffer some symptoms
7
Q
- What is one benefit of being heterozygous for Sickle Cell Disease?
A
- Heterozygotes are less susceptible to the Malaria
parasite - this gives them a survival advantage in the
Mediterranean and Sub-Tropical regions - these regions have many Malaria vectors
- this is result of natural selection
8
Q
- What is Haemoglobin?
A
- it is a globular protein
- it consists of 4 polypeptides
- 2 alpha chains
- 2 beta chains
9
Q
- What is Thalassaemia?
A
- this is an inherited blood disorder
- it is caused when the body doesn’t make enough
haemoglobin
10
Q
- What are the symptoms of Thalassaemia?
A
- unusual bone growth
- enlarged forehead or cheeks
- weak, fragile bones
- osteoporosis
- reduced fertility
11
Q
- What is Cystic Fibrosis?
A
- this is the most common lethal genetic disease in the
United States
12
Q
- How many people of European Descent suffer from Cystic Fibrosis?
A
- 1 in every 2 500 people
13
Q
- What does the Cystic Fibrosis Allele result in?
A
- it results in defective or absent chloride transport
channels in the plasma membrane
14
Q
- What is Cystic Fibrosis characterised by?
A
- scarring
(fibrosis) - cyst formation within the pancreas
15
Q
- What are the 2 major symptoms of Cystic Fibrosis?
A
- mucus buildup in some internal organs
- abnormal absorption of nutrients in the small intestine
16
Q
- What does CTR-1 stand for?
A
- Copper Transporter Protein 1
17
Q
- Where is the Copper Transporter Protein 1 located?
A
- this channel protein is located mostly on intestinal
epithelial cells - these cells are responsible for Copper (Cu²⁺0
absorption
18
Q
- What leads to CTR-1 deficiency?
A
- an autosomal recessive disorder due to mutations in
the CTR-1 protein - these mutations result in defective copper transport
proteins
19
Q
- What is Copper?
A
- it is an essential trace element
IT IS RESPONSIBLE FOR:
- embryonic development
- myelin production
- mitochondrial and cellular respiration enzyme
functions
20
Q
- What are the symptoms of CTR-1 deficiency?
A
- neurological degeneration
- severe developmental delay
21
Q
- What are Autosomal Dominant Disorders?
A
- they are inherited disorders
- they are less common than Autosomal Recessive
Disorders - the affected individual usually does not survive until
adulthood - the affected individual often does not reproduce
- these disorders are caused by dominant alleles
22
Q
- What is an individual with an Autosomal Dominant Disorder plagued with even if they survive till adulthood?
A
- the autosomal disorder presents itself in the
phenotype - this goes against the natural selection principles
23
Q
- Why are Autosomal Dominant Disorders rare?
A
- the affected individual usually dies before mating
- this means that they cannot pass on the gene
24
Q
- What are exceptions when it comes to Autosomal Dominant Disorders?
A
- some disorders can express symptoms late in life
- this is known as a late onset of symptoms
- EG: Huntington Disease
25
Q
- What can be said about dominant alleles that cause a lethal disease?
A
- they are rare
- they arise by mutation
26
Q
- What are 2 examples of Autosomal Dominant Disorders?
A
- Huntington’s Disease
- Achondroplasia
27
Q
- What is Achondroplasia?
A
- this is a form of dwarfism
- it is caused by a rare dominant allele
28
Q
- What is Huntington’s Disease?
A
- this is a neurodegenerative disorder
- it is a degenerative disease of the nervois system
29
Q
- When does a person with Huntington’s begin to experience symptoms?
A
- the disease has no phenotypic effects until the
individual is about 35 to 40 years of age - the disease is late onset
30
Q
- What does the timing of the onset of the symptoms of the disease affect?
A
- it affects the inheritance
- late onset allows mating and offspring production
31
Q
- What happens to patients with Huntington’s disease when the deterioration of the nervous system starts?
A
- the effects are irreversible
- the effects are fatal
