There are many different kinds of birth disorders that are inherited by the parents, called hereditary disorders. There are also disorders that are not inherently linked to the parents. These are non-hereditary disorders, which are quite common. How do people develop a non-hereditary disorder?
Sometimes mistakes happen during the process of Meiosis which is the formation of gamete cells. Gametes are specific male and female cells that can unite with a gamete from the opposite sex during fertilization.
There are 23 chromosomes in each gamete. During meiosis in a process called “crossing over” the chromatids are basically shuffled and they exchange certain genes. Normally after this process, the chromatids will separate and move to opposite ends of the cell to finish the formation of gametes. Sometimes however, the chromatids can become stuck together and they don’t separate. This results in one gamete having 22 chromosomes and another having 24. This process is referred to as nondisjunction.
During fertilization, if a gamete cell unites with another gamete that is missing a chromosome, this is called monosomy. This results in monosomic disorders which are usually fatal. However, there is one monosomic disorder that is not life threatening.
When a gamete cell is missing an X chromosome and it is used in fertilization, this results in Turner’s Syndrome. A woman who has Turner’s Syndrome is not able to reproduce.
So now you know how non-hereditary disorders work. The one thing we do not know about these disorders is how to determine if your child will have one. We are still limited to just predictions.