Mutations and inherited diseases
Sickle cell anaemia
Sickle cell anaemia is an inherited disease that affects the shape of the blood cells.
The sick cell red blood cell is sickle shaped.
The sickle shape of sickle cell anaemia red blood cells reduces their ability to carry oxygen and the cells become stuck in the capillaries. This causes pain and results in the person dying before they reach a reproductive age. However, carriers of the sickle cell gene are more likely to survive malaria, meaning the disease has not disappeared.
Huntington’s disease is a brain disease.
Hunting (Huntington’s) a brain.
Huntington’s disease causes mental deterioration and symptoms include shaking, clumsiness, memory loss, an inability to concentrate and mood swings. As it is caused by a dominant allele if just one parent is a carrier of the allele then there’s a 50% chance their children will suffer from the disease. Symptoms don’t show until later in life (usually after 40) so the disease is often passed onto children before a parent knows they are a carrier of the disease.