UNDERSTANDING INHERITANCE PATTERNS
FACTS ABOUT INHERITED DISORDERS
- Autosomal conditions are caused by gene mutations located on autosomal chromosomes.
- In autosomal recessive disorders, both copies of the gene must be mutated in order to cause a disease.
- In an autosomal dominant inheritance, one mutated copy of the gene is sufficient to cause the disease.
- An individual who has a mutation in only one copy of a gene is considered a carrier.
- Carriers are typically asymptomatic, but they have a risk of passing the mutated gene to their children.
- Although these disorders are relatively rare, an average person may be a carrier for at least eight significantly detrimental disorders.
- When both parents are carriers, there is a 25% chance that they will have an affected child; this couple has a 50% of having a child who is also a carrier for the disease.
ETHNICITY AND GENETIC DISEASES
Some genetic diseases are more common in particular ethnic groups compared to the general population. This is because people in the same ethnic group share some genetic information inherited from common ancestors. Common examples include:
- Ashkenazi Jewish – Tay-Sachs Disease, Cystic Fibrosis
- African – Thalassemia, Sickle Cell Disease
- Asian Thalassemia
- Caucasian – Cystic Fibrosis
- Mediterranean – Thalassemia, Sickle Cell Disease