What is genetic counseling?
Genetic counseling is the process of determining the risk you have of passing on an inheritable disease to your baby. Genetic counseling involves a specially trained healthcare professional who identifies families at risk, investigates the problem present in the family, interprets information about the disorder, analyzes inheritance patterns and risks of recurrence, and reviews available options with the family.
Who should seek genetic counseling?
According to the Centers for Disease Control and Prevention (CDC), approximately 3% of babies born in the United States will have a birth defect. Genetic counseling is not necessary for the majority of couples who are pregnant or planning on getting pregnant. Genetic counseling should be considered by couples who have one or more of the following risk factors:
- Abnormal results are obtained from routine prenatal testing
- Amniocentesis results identify a chromosomal defect
- An inherited disease is present in a close family member
- If either partner has already had a child with a birth defect or genetic disorder
- If the mother is over 35 years old
The following represents some of the ethnic groups which have a greater chance for certain genetic defects:
|Ethnic Group||Genetic Defect|
|African Americans||Sickle Cell Anemia|
|Central or Eastern Jews||Tay – Sachs disease|
|Italian, Greek, Middle Eastern||Thalassemia|
What is involved in genetic counseling?
When you are working with a genetic counselor there are a number of things you should expect. You should start with your blood relatives on both sides to begin creating a comprehensive background on specific diseases and why they occurred. This is probably the most important piece of evaluating genetic risks.
To help facilitate this evaluation, your healthcare provider will probably ask some of the following questions:
- Do you have a history of diabetes, hypertension, cancer or twins?
- Are there any diseases that seem to run in your family?
- Is there a history of genetic disease like cystic fibrosis, hemophilia, or muscular dystrophy?
- Is there anyone with mental retardation or any kind of birth defect?
- Have any of your sisters, cousins, or other relatives had problems with their pregnancies?
- Are your parents alive, and are they healthy?
- What is your ethnic background?
- Is there any reason that you suspect that your baby may be born with a birth defect or other medical problem?
What are genes and chromosomes?
A gene is a segment of DNA that is coded to pass along a certain trait; it has a specific task (i.e. determining the color of your eyes). Genes are the simplest building blocks of heredity. They are grouped together in specific patterns within a person’s chromosomes, forming the unique “blueprint” for every physical and biological characteristic of that person.
Chromosomes are made up of deoxyribonucleic acid (DNA) molecules. Humans have 46 chromosomes arranged in pairs in every living cell of our bodies. When the egg and sperm join at conception, half of each chromosomal pair is inherited from each parent.
What causes genetic disorders?
Genetic disorders may be caused by of a variety of reasons. Genetic disorders may be caused by abnormalities in the chromosomes, which are referred to as chromosomal abnormalities. Disorders may also be caused by a single gene, which may be identified as dominant, recessive or X-linked disorders.
Dominant Disorders: One gene is defective and it overrides the normal gene
Recessive Disorders: Both genes in the pair are defective
X-linked Disorders: A defective gene is on an X chromosome, which may be recessive or dominant
The following is a list of potential explanations for birth defects or genetic disorders:
- Spontaneous mutation
- Errors in cell division
- Single gene changes because of environmental exposure to chemicals or radiation
- Defect in the development of the sperm or the egg
- Recreational drug use
- Exposure to lead or industrial chemicals