Sickle–cell anemia– A type of genetic disorder
Sickle cell anemia (sickle cell disease) is a disorder of the blood caused by an inherited abnormal hemoglobin (an oxygen–carrying protein within the red blood cells). A genetic disorder or inherited disorder is a disease that is caused by an abnormality in an individual's DNA.
Abnormalities can range from a small mutation in a single gene to the addition or subtraction of an entire chromosome or set of chromosomes. Thousands of genetic disorders are known to be inherited.
Two types of genetic disorders can be seen: Autosomal recessive and autosomal dominant. Autosomal recessive is one of several ways that a trait, disorder, or disease can be passed down through families. An autosomal recessive disorder means two copies of an abnormal gene must be present in order for the disease or trait to develop. Examples of autosomal recessive disorders include: Cystic Fibrosis, Sickle – cell disease, Phenylketonuria.
Autosomal dominant is one of several ways that a trait or disorder can be passed down through families. If a disease is autosomal dominant, it means you only need to get the abnormal gene from one parent in order for you to inherit the disease. One of the parents may often have the disease. Examples of autosomal dominant disorders include: Achondroplasia, Huntington's Chorea, Multifactorial Disorders (Many people are susceptible to diseases that have a multifactorial basis – a genetic component plus a significant environmental influence. Heart disease, diabetes, cancer, alcoholism, certain mental illnesses such as schizophrenia)