Quick Tips for Risk Assessment
Genetic "red flags" are indications that there might be increased genetic risk in an individual or family. The primary red flag for most common diseases is a large number of affected relatives with a close degree of relationship. This can indicate unusually high genetic and/or environmental risk, and the risk for close relatives may be increased dramatically. Generally, the same red flags increase risk for Mendelian and common disorders.
Some genetic red flags include:
Family history of multiple affected family members with the same or related disorders, which may or may not follow an identifiable pattern in the family
- Such a pattern indicates increased risk, whether through genetic or environmental risk factors, or a combination of genes and environment.
- Examples: Three family members in two generations with heart disease; a father and son with diabetes
Earlier age at onset of disease than expected
- Disorders that arise at a younger age than expected may occur because of a genetic predisposition that makes an individual more susceptible to environmental exposures.
- Examples: Heart disease occurring in the 30s; lung cancer in the 40s
Condition in the less-often-affected sex
- A disorder that occurs in the less common sex may occur because of a genetic predisposition that overrides other hormonal, developmental and environmental factors that contribute to its occurrence.
- Examples: Breast cancer in a male; persistent stuttering in a female
Disease in the absence of known risk factors
- Genetic predisposition may lead to the occurrence of a disorder in the absence of obvious environmental factors.
- Example: hyperlipidemia in an individual with an ideal diet and exercise regimen
Ethnic predisposition to certain genetic disorders
- Some genetic disorders are more common in certain ethnic groups. Awareness of a patient’s ethnicity or ancestral background can aid in recommending genetic testing and evaluation of genetic conditions.
- Example: lactose intolerance in an individual of African ancestry
Close biological relationship between parents (i.e., consanguinity)
- Consanguinity is a relationship by blood or a common ancestor. Because relatives are more likely to share the same genes, children from a consanguineous couple related as first cousins or closer have an increased risk of having an autosomal recessive condition.
- Examples: autosomal recessive disorders, including those that are part of the newborn screen (including MCADD and cystic fibrosis), are more common in consanguineous couples.