From the Guidelines
Prevention of genetic disorders can be achieved through a combination of genetic counseling, prenatal testing, and reproductive planning.
Key Methods
- Genetic counseling is meant to provide individuals and families at risk of a genetic disorder with information on the nature, mode of inheritance, and implications of that disorder to help them make informed medical and personal decisions 1.
- Prenatal testing such as chorionic villus sampling (CVS) or amniocentesis can be performed between 10-20 weeks of gestation to detect chromosomal abnormalities, allowing for informed decision-making regarding pregnancy continuation.
- Pre-implantation genetic diagnosis is possible if a mosaic or heterozygous pathogenic variant has been identified in a patient with a genetic disorder, and many options are available, with their relative merits to be discussed before pregnancy 1.
Additional Considerations
- For individuals with a family history of genetic disorders, folic acid supplementation at a dose of 4-5 mg per day, initiated at least one month prior to conception and continued through the first trimester, can reduce the risk of neural tube defects.
- Genetic screening tests can detect chromosomal abnormalities, allowing for informed decision-making regarding pregnancy continuation.
- Reproductive planning and family planning should be promoted based on the patient’s reproductive life plan, including effective contraceptive use and discussion of emergency contraception 1.
- Preimplantation genetic testing for monogenic disorders (PGT-M) can prevent the transmission of inherited diseases, with recent developments in molecular biological technologies and genetic diagnostic methods enabling improvements in new strategies for PGT-M 1.
From the Research
Methods for Preventing Genetic Disorders
The following methods can be used to prevent or manage genetic disorders:
- Genetic counseling and testing for couples with a family history of genetic disorders, a previously affected fetus or child, or a history of recurrent miscarriage 2, 3
- Prenatal serum marker screening for neural tube defects and aneuploidy 2, 4
- Amniocentesis or chorionic villus sampling for women at increased risk for aneuploidy 2, 4, 5, 6
- Folic acid supplementation beginning in the preconception period to reduce the incidence of neural tube defects 2
- Avoiding smoking, alcohol, and drug use during pregnancy 2
- Routine fetal heart auscultation, urinalysis, and assessment of maternal weight, blood pressure, and fundal height 2
- ABO and Rh blood typing and screening for anemia during the first prenatal visit 2
- Expanded carrier screening panels and non-invasive cell-free fetal DNA-based screening for aneuploidy and single-gene disorders 4
- Chromosomal microarray analysis and whole-exome sequencing for diagnosing genetic conditions on samples obtained through amniocentesis or chorionic villus sampling 4
Prenatal Diagnostic Testing
Prenatal genetic diagnostic testing is intended to determine whether a specific genetic disorder or condition is present in the fetus 5, 6. This testing can detect a broad range of genetic disorders, including Down syndrome (trisomy 21) 5, 6. The objective of prenatal genetic testing is to detect health problems that could affect the woman, fetus, or newborn and provide the patient and her obstetrician-gynecologist or other obstetric care provider with enough information to allow a fully informed decision about pregnancy management 5, 6.
Benefits and Limitations of Prenatal Genetic Testing
Prenatal genetic testing has many benefits, including reassuring patients when results are normal, identifying disorders for which prenatal treatment may provide benefit, optimizing neonatal outcomes, and allowing the opportunity for pregnancy termination 5, 6. However, prenatal genetic testing cannot identify all abnormalities or problems in a fetus, and any testing should be focused on the individual patient's risks, reproductive goals, and preferences 5, 6. It is also important that patients understand the benefits and limitations of all prenatal screening and diagnostic testing, including the conditions for which tests are available and the conditions that will not be detected by testing 5, 6.