Fertility treatment is a unique opportunity to detect and prevent the transmission of genetic diseases to future children. In addition to genetic screening, embryo testing can be done during in vitro fertilization-IVF to detect those that do not carry the disease and rule out unhealthy ones. This process is called PGD-Preimplantation Genetic Diagnosis. Genetic concerns arise due to genetic or family history or are found during routine screening before fertility treatments. As technology advances, the main challenge remains the identification of carriers of genetic diseases using a comprehensive history and screening by a reproductive endocrinologist and possibly genetic counseling. Be prepared, you and your partner, to tell your reproductive endocrinologist about your disease history and that of other family members.
Gina-The Genetic Information Nondiscrimination Act of 2008, which went into effect in 2010, prohibits discrimination in health coverage or employment based on genetic information.
Genetic screening, who is at risk?
Routine genetic screening for each individual or couple who wants a pregnancy. Screening is based on common genetic problems based on ethnic group of ancestry. Initially, only one couple should be tested, and if the test is positive, the other couple should be tested.
Everyone should be screened for cystic fibrosis-CF and possibly spinal muscular atrophy-SMA1.
Ashkenazi Jewish ancestry should be screened for Canavan disease, CF, Tay Sch disease, familial dysautonomia. Some extend this screening to Fanconi Anemia, Bloom Anemia, Gaucher Anemia, Neiman Pick Anemia, Mucolipoidosis IV, Glycogen Storage Disease Ia, Maple Serum Urine Disease and Familial Hyperinsulinism, Nemaline Myopathy, DLD Deficiency, Joubert and Usher Syndromes .
Sephardic Jewish ancestry should be screened for CF and Tay Sach disease. Some add familial Mediterranean fever, ataxia telangiectasia, Fanconi anemia, 11B hydroxylase deficiency, glycogen storage disease IIIa, factor VII deficiency, and other diseases.
French-Canadian ancestry should be screened for Tay Sach disease
Mediterranean ancestry (Greek, Italian, Arabic…) should be screened for Thalassemia B,
Asian descent (Japanese, Pakistani, Chinese…) Thalassemia a,
African-Americans should be screened for sickle cell disease
Decreased ovarian reserve. Screening of young women with decreased ovarian reserve for the fragile X syndrome premutation and also for chromosomal abnormalities, eg, mosaic Turner syndrome, using an a-karyotype test to detect the number and shape of chromosomal abnormalities, should be considered. chromosomes.
Male factor infertility. Men with very low counts of less than 5 million per mL or no sperm in the ejaculate should be screened for CF and its variants, Kleinfelter syndrome, and Y chromosome microdeletions.
Recurrent pregnancy loss. Sometimes in a couple reporting two or more miscarriages, especially early in the first trimester, one partner may have a hidden chromosomal abnormality. One chromosome is carried on top of another, they are passed on to the baby together, increasing the risk of the newborn having an additional chromosomal trisomy.
A parent, a previous child, or a family member affected with a genetic disease. If the disease is well defined, the affected individual must first be tested to determine the exact DNA alteration that causes the disease: the mutation. The pair is then tested for the same mutation.
One of the parents or a child affected with chromosomal abnormalities.. If a previous baby had a chromosomal abnormality, both patent karyotypes should be obtained to rule out one of them having an abnormality and to prevent its recurrence in future babies.
A parent or family member who has an inherited predisposition to cancer.. Some people have an inherited predisposition to cancer due to the inheritance of certain mutations. Multiple family members over multiple generations have typically been diagnosed with specific cancers at a younger age, for example, <50 years. Examples of these are BRCA 1 and 2 for breast and ovarian cancers, the FAP gene for colon cancer... These mutations carry a very high risk of cancer throughout life and can be detected. Its transmission to future children can be prevented.
Previous child diagnosed with certain types of cancer. Families with a child diagnosed with cancer may consider genetic testing for two reasons. Diagnosis of a specific mutation in the child diagnosed with cancer, for example, retinoblastoma, can prevent transmission of the cancer to future children. On the other hand, some children diagnosed with cancer, for example leukemia, require a bone marrow transplant from a genetically close donor. Some families choose to conceive with a child who is genetically compatible with their diagnosed sibling so that the child’s umbilical cord blood can be used as a bone marrow donor for their brother or sister.
Genetic risk assessment methods.
Blood tests for genetic screening. The blood cells are tested to detect the individual’s carrier status. This test can identify if the individual carries a defective gene for the disease in question. If the screening tests are positive, it is best for the couple to receive genetic counseling. This will often inform them of the risk of transmission to offspring so they can make an informed decision about further testing or treatment.
Embryo biopsy and DNA test. One or two cells are removed from a day 3 cleavage stage embryo and their DNA is analyzed for one or more specific mutations. Affected embryos are excluded from uterine replacement while healthy ones are used for transfer. Results are obtained in 1-2 days and healthy embryos are transferred to the uterus.
Because the amount of genetic material available for testing is small, these are considered screening, not diagnostic, methods. antenatal diagnosis It is commonly recommended during the first or early second trimester of pregnancy. This usually involves blood tests for the mother, amniocentesis, or chorion villus sampling-CVS to analyze the genetic material of the fetus.
Genetic risk management during fertility treatment
Genetic abnormalities that do not require a change in the infertility treatment plan. If 1. Only one parent is a carrier of the genetic mutation and the other is not a carrier of the mutation for an autosomal recessive disease (a disease that requires two abnormal copies to manifest), or 2. The couple does not wish to undergo any genetic testing neither PGD or 3 .prefers to perform these tests after pregnancy is established, so the treatment plan does not need to be altered for a well-informed couple.
Genetic abnormalities that require a change in infertility treatment plan. For couples who carry a genetic mutation with a significant risk of transmission to children and want to avoid or minimize this risk, the plan should be changed. Fertility treatment must be changed to IVF to allow testing of the embryos. After ovarian stimulation, the eggs are analyzed by polar body biopsy or the embryos by embryo biopsy. When the results are obtained, the healthy embryos are transferred to the uterus. In some genetic diseases that manifest preferentially in certain sexes, such as Hemophilia or Duchenne myopathy, which affect boys more than girls, the disease can be avoided by transferring embryos of the opposite sex.
Routine genetic risk assessment, beginning with a complete genetic and family history by a reproductive endocrinologist, infertility specialist, or genetic counselor, can prevent the transmission of genetic diseases to future children and can contribute significantly to your health and well-being . In addition, many ethical and social issues beset the application of genetic testing and PGD programs and have not been discussed here. This is general in nature and is not a substitute for consultation with a qualified medical adviser.
