Apart from getting one’s physical health in shape, another important step for couples is being informed about family histories from both sides. Read how genes affect pregnancy.
Why is building a family tree important?
Acquiring medical information about parents, grandparents, siblings, aunts and uncles, cousins and other key relatives helps a couple understand if there is a history of an inherited disorder from the family tree of either partner.
Inherited disorders are passed down a family tree through genes, the genetic material arranged on chromosomes in every cell. Genes provide instructions for making proteins necessary for determining structure and function of different cells in the body.
Genes are responsible for all characteristics that are inherited. Every individual carries the full genetic instruction set (referred to as the human genome) on 23 pairs of chromosomes, each carrying about 20,000 – 25,000 genes.
How inheritance works
At time of conception, an embryo is formed by the combination of 23 chromosomes from the mother’s egg and 23 chromosomes from the father’s sperm, making the complete 23 pairs of chromosomes for the future baby. When chromosomes join together, a random exchange of genes occurs between each pair of chromosome; while the traits on the genes are passed on from one generation to another, the random rearrangement of genes on chromosomes at time of fertilisation gives each person his/her unique characteristics (Identical twins, however, have the same genetic combination).
How do genetic disorders occur?
Each healthy gene is composed of genetic molecules arranged in a specific pattern on a particular chromosome. Genetic disorders take place when the genetic code of a gene is faulty, i.e. the gene undergoes changes or mutations. Genetic disorders are defined by the gene affected, by the pattern of inheritance (dominant or recessive) and the type of chromosome it is present or absent on (passed down via X chromosome).
Genetic testing and what it means
Genetic counselling allows couples with a family history of genetic disease to understand their risk of getting the disease or having a child with the inherited disease. Genetic tests are available to determine if either partner is carrying faulty genes associated with certain genetic diseases. Tests available include:
- Carrier screening – A blood test is performed on healthy-looking couples to determine if they carry a gene mutation that is recessive in nature (hidden due to the other-normal gene on the chromosome pair). A carrier mother and a carrier father can have children that have the disease. However, the disease will not affect a child if none or only one partner tests positive. Carrier screening is done for diseases like cystic fibrosis, sickle-cell anaemia, and Tay-Sachs disease.
- Prenatal diagnostic testing – A pregnant woman may undergo amniocentesis and chorionic villus sampling (CVS) to diagnose the occurrence of certain chromosomal disorders like Down’s syndrome.
- Predictive testing – This form of test looks for gene mutations in a couple that increase their risk of developing late-onset diseases like diabetes, cancer (breast cancer, ovarian cancer) or Huntington’s disease, which often run in families. If tested positive, the couple can make healthier lifestyle choices to prevent the disorder and ensure a healthy pregnancy.
Get in touch with Credihealth today and get genetic testing for your baby!
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“Pregnancy Information and Testing,” http://www.genetics.edu.au/Genetic-conditions-support-groups/Pregnancy-Information-and-Testing
“What is genetic testing?” Genetic Disease Foundation http://www.knowyourgenes.org/genetic-testing-full.shtml