From the Guidelines
Interbreeding between closely related individuals significantly increases the risk of birth defects, and genetic counseling is strongly recommended for related couples considering having children. The risk of birth defects is higher in offspring of related individuals due to the increased chance of inheriting two copies of harmful recessive genes 1. First-degree relatives (parents-children, siblings) have a higher risk of serious birth defects in offspring, while more distant relatives (cousins) have a lower but still elevated risk compared to the general population.
Key Risks and Considerations
- The increased risk of birth defects in offspring of related individuals includes intellectual disability, heart abnormalities, skeletal malformations, and metabolic disorders.
- Genetic counseling can assess specific risks based on family history and possibly recommend genetic testing to identify potential issues before conception or during pregnancy 1.
- A family or personal history of birth defects, chromosomal abnormalities, significant hearing or vision loss, mental retardation, or autism are indications for genetic referral 1.
Recommendations for Healthcare Providers
- Discuss recurrence risks and testing options with couples who have a family or personal history of birth defects or other genetic conditions 1.
- Consider genetic counseling for related couples considering having children to assess specific risks and recommend genetic testing if necessary.
- Be aware of the potential risks and consequences of interbreeding between closely related individuals, including the increased risk of birth defects and the potential long-term burden on the child's health and well-being 1.
From the Research
Interbreeding Birth Defects
- Interbreeding can increase the risk of birth defects due to the concentration of similar genetic traits 2, 3.
- Prenatal genetic screening and testing can help identify potential genetic disorders or conditions in the fetus, including those related to interbreeding 4, 5.
- Screening tests, such as cell-free DNA (cfDNA) testing, can evaluate the risk of certain genetic conditions, including aneuploidy and single-gene disorders 6.
- Diagnostic testing options, including karyotype, prenatal microarray, and next-generation sequencing, can provide more detailed information about the fetus's genetic makeup 5.
- It is essential for patients to understand the benefits and limitations of prenatal screening and diagnostic testing, as well as the conditions for which tests are available and those that will not be detected by testing 3, 6.