Maternal

• Genetics is a branch of science that studies genes and the pattern of inheritance of particular diseases.
• Chromosomes carry the hereditary information (genes) and are the basic units of inheritance that determine both the physical and cognitive characteristics of people.
• DNA forms the genetic material.
• Genomics addresses the functions and interactions of all the genes in an organism.
• A normal genome is abbreviated as 46XX or 46XY.
• Treatment options for children with genetic disorders range from medical therapy during pregnancy, such as fetal interventions, to surgery immediately after birth.
• A multidisciplinary, collaborative healthcare team, including genetic counselors, imaging specialists, fetal specialists, fetal and neonatal surgeons as needed, and neonatologists and pediatricians experienced in the treatment of children with genetic disorders, provides care for children with genetic disorders.
• Support services, such as counseling and financial assistance, are available for families of children with genetic disorders.
• If a chromosomal aberration exists, it is listed after the sex chromosome pattern, for example, Down syndrome is an extra chromosome 21, abbreviated as 47XX21 or 47XY21.
• Phenotype is the person’s outward appearance.
• Genotype is the person’s actual gene composition.
• Homozygous refers to a person who has two like genes for a trait on two like chromosomes.
• Heterozygous refers to a person whose genes differ, for example, a healthy gene from the mother and an unhealthy gene from the father, or vice versa.
• Inherited or genetic disorders can be passed from one generation to the next.
• Karyotype is the schematic arrangements of the chromosomes within a cell to demonstrate their numbers and morphology.
• Hereditary refers to genetic information derived from parents.
• Familial refers to genetic information transmitted in the gametes through generations.
• Congenital refers to genetic information present at birth, not always genetically determined, for example, congenital syphilis, toxoplasmosis.
• Diagnostic tests can detect if certain genetic disorders are actually present in the baby.
• Multifactorial or complex disorders are caused by a combination of genetic predispositions and environmental factors, which makes it harder to predict who may be at risk, examples include heart defects, cleft lip or cleft palate, and spina bifida.
• Teratogenic disorders occur when the baby is exposed to substances during pregnancy that cause abnormalities, otherwise known as “teratogens,” babies are very sensitive in the first trimester, when all of the organs are developing, teratogens include alcohol, drugs, lead, high levels of radiation exposure, and certain medications, infections and toxic substances.
• Screening tests are available to all women, even those who do not have any known risk factors, to check the risk of their baby having certain genetic disorders.
• Genetic inheritance can occur from multiple gene combinations possibly combined with environmental factors.
• Some conditions have a predisposition to occur more frequently in one sex, but they can occur in either sex.
• Chromosomal abnormalities occur where there are missing or extra chromosomes, or pieces of chromosomes, Down syndrome, the most common chromosomal abnormality, is caused by an extra chromosome number 21.
• A family history may reveal no set pattern in multifactorial inheritance.
• Risk factors for genetic disorders include family history, prior child with a genetic disorder, one parent having a chromosomal abnormality, advanced maternal or paternal age, multiple miscarriages or stillbirth, and prenatal exposure to drugs, alcohol, or other environmental factors.
• Chromosomal abnormalities can be inherited from a parent or they can happen by chance.
• Single gene disorders occur when a change in one gene causes a disease, examples include cystic fibrosis, sickle cell anemia, and hemophilia.
• Prenatal genetic screens are a series of first and second trimester screens that use blood samples from the mother as well as ultrasounds to check the baby’s risk of having certain common genetic disorders, such as Down syndrome and certain birth defects, like spina bifida.
• Noninvasive Prenatal Testing (NIPT) or cell-free DNA screening is a blood test that checks DNA from the placenta that is found in the mother’s blood, screens for the most common chromosome abnormalities, and is most commonly used in high-risk pregnancies.
• Prenatal Chromosome Analysis (Karyotype) is a common genetic test performed on cells obtained from an amniocentesis or CVS that can detect large changes in the chromosomes, such as an extra or missing chromosome or a change in how the chromosomes are put together.
• Fetal genomic or whole-exome sequencing (WES) is a diagnostic test for pregnancies with complex fetal conditions that checks almost all of a baby’s genes.
• Chorionic villus sampling tests a sample of tissue taken from the placenta in the first trimester.
• Prenatal Chromosomal Microarray Analysis (CMA) is a more detailed test performed on cells obtained from an amniocentesis or CVS and tries to detect if any pieces of chromosomes are missing or extra, these extra or missing pieces may be too small to see on a karyotype alone.
• Genetic counseling involves assessing your personal risk of having a baby with a genetic disorder, reviewing your testing options, coordinating genetic screenings and diagnostic tests and interpreting the results, providing emotional support and educational resources for you and your family, and helping you make informed decisions about your pregnancy and your baby’s treatment, and preparing for appropriate medical care.
• Diagnostic tests are performed during pregnancy to detect if certain genetic disorders are present in the baby, such as cystic fibrosis or Down syndrome, and are generally safe procedures when performed by an experienced physician.
• Treatment for fetal genetic disorders depends on the genetic disorder and the individual pregnancy, and may include specialized care from a maternal-fetal medicine physician, individualized care based on the genetic disorder, your pregnancy, and your family’s preferences.
• Fetal blood sampling or percutaneous umbilical blood sampling (PUBS) uses a blood sample from the baby’s umbilical cord to test for genetic disorders, usually done when amniocentesis or chorionic villus sampling are not possible.
• Amniocentesis tests a sample of the amniotic fluid taken from the womb in the second trimester.