Let's work out how you can get these disorders, no, I am not going to call it a disease 'cos you can't catch it like a bacteria, fungus or virus. You don't get it from someone sneezing! You get these disorders from faulty alleles passed down to you from your parents. Remember though, it is all down to probability. It's the chance that someone has of getting the disorder from their parents alleles.
So, what is the chance? Well, sickle cell disorder and cystic fibrosis are both caused by faulty alleles which are recessive. This means that you have to get 2 copies of the recessive allele to get the disorder. You have to get one copy of the allele from your mum and one copy for the allele from your dad. As it's recessive, if you only get one copy of the allele then the other would be dominant therefore you wouldn't get the disorder. You would however still carry the recessive allele so you would be a carrier.
Sickle cell disorder
Sickle cells results in the red blood cell being a sickle shape - these are the pink banana shaped cells in the photograph. The sickle cell is caused by a mutation in the haemoglobin. Haemoglobin is the pigment in the red blood cell that carries Oxygen so these mutated cells can carry less oxygen that the normal red blood cells which are bi-concave shaped. The sickle cells are also not as flexible as normal red blood cells so sometimes get stuck in blood vessels.
Symptoms of sickle cell
People with these disease easily become tired and short of breath because they cannot carry enough oxygen around their body for respiration.
They also have at times very painful joints because the sickle cells have stuck together and blocked some blood vessels - this could be fatal!
Cystic fibrosis symptoms
This is another disorder caused by a recessive allele. Remember you must get 2 recessive alleles to get this disease - just like Sickle Cell disease. So it's people who have 2 copies of these diseases who suffer from it.
In cystic fibrosis the lungs get clogged up with thick mucus. This makes it difficult to breathe. The mucus also traps pathogens which leads to infections. This thick mucus will also block some of the tubes that carry enzymes to the small intestine. Remember, enzymes break down large molecules in food into smaller molecules. Example, proteins are broken down into amino acids. If you are not absorbing enough nutrients then you will not put on weight.
Family pedigree charts
Symptoms of sickle cell
People with these disease easily become tired and short of breath because they cannot carry enough oxygen around their body for respiration.
They also have at times very painful joints because the sickle cells have stuck together and blocked some blood vessels - this could be fatal!
Cystic fibrosis symptoms
This is another disorder caused by a recessive allele. Remember you must get 2 recessive alleles to get this disease - just like Sickle Cell disease. So it's people who have 2 copies of these diseases who suffer from it.
In cystic fibrosis the lungs get clogged up with thick mucus. This makes it difficult to breathe. The mucus also traps pathogens which leads to infections. This thick mucus will also block some of the tubes that carry enzymes to the small intestine. Remember, enzymes break down large molecules in food into smaller molecules. Example, proteins are broken down into amino acids. If you are not absorbing enough nutrients then you will not put on weight.
Family pedigree charts
Doctors create pedigree charts like the one above to show how a genetic disorder is inherited and to show how the disease is passed on through the family. They can then work out the chances, the probability that a person may inherit this disease. This is called a Pedigree analysis. They could also inform parents of the probability of them passing on the disease to future children. This would help them decide if they want to have babies or not. What a horrible decision to have to make eh?!
